Starre Varten, author of the Eco-Chick Guide to Life, writing at Mother Nature Network poses the question – is it acceptable now to wear pyjamas all day?

Surely not. And yet the trend for stay at home mums to turn up at the school gate in their nightwear is increasing, and teens have been seen shopping on Sundays in their PJs.

Of course the trend towards casual clothing has accelerated, and women now feel completely comfortable to walk around all day in leggings and yoga pants, where a few years ago such clothing would have been gym attire only. And as Varten points out, casual clothing breaks down class and income distinctions and allows everybody to be treated equally. In the days when rich people dressed one way and poor another, social distinctions were clearly made on sight – now that we all wear jeans and T-shirts, even the President of the USA (on his days off) wears hoodies, we’re told – we all have the opportunity to interact without barriers created by clothing judgements.

On the other hand, there’s no doubt that overly casual attire will still lead to social isolation. The mothers who don’t get out of their sleepwear to collect their children from school may struggle to obtain employment or other opportunities when they seek them if their habit of dressing down has become ingrained because it can suggest to others that these are people who have no interest in achievement and little desire to emulate others.

So where do we draw the line? The answer may be simple – don’t wear your PJs in the street, instead, wear your streetwear to bed! A camisole top and shorts, for women, or short sleeved T-shirt and shorts for men, can be as comfortable as nightwear and if you really can’t be bothered to change your clothes, allows you to leave the house without earning yourself a reputation for idleness.

Clare Balding, BBC presenter, has said in the Radio Times that, ‘Female faces will dominate the British medal haul in 2012’ in reference to the London Olympics. Balding pointed out that women’s ability to take part in codified competitive sport is nearly 900 years behind that of men, but that women are likely to lead the medal tables for Britain.

The impact of sport on wider society is easily seen through sports clothing: the hoody, once the preserve of boxers, the rugby shirt and polo shirt and jogging bottoms or trackies, worn originally by track athletes, have all become part of mainstream casual clothing.

This new freedom to play sport and wear sporting clothing has given many women a new freedom to invest in their bodies as competitive instruments and that has led to a change in their approach to clothing. Many more women now wear what is called Sports Luxe and it is a key feature of the West Coast Cooler Fashion Week in Belfast. Sports Luxe is clothing with a dual purpose: looking good and feeling good in times of activity. Designers such as Marc Jacobs, Hugo Boss and Philip Lim have made this particular style their own by using rich colours and unusual fabrics: plum coloured jogging pants or tuxedo shirts that wick away sweat, for example.

For those who can’t afford designer clothing a stylish women’s polo shirt worn with jeans or jeggings and a pashmina, or casual trousers or leggings teamed with a cashmere top and designer trainers both work as Sports Luxe statements.

Two nations divided by a common language – and by clothing. As part of our New Year’s Resolutions many of us decide to smarten up and Esquire had a clothing guide for men that made us laugh, cheer and scratch our heads.

Some of the items on their list we had no argument with:

7. A rugby shirt is the most masculine thing a man can wear.

For sure. And a rugby shirt is always acceptable socially.

And then there’s:

22. Always tuck: polo and dress shirts that hang below your hip. Never tuck: sweaters and turtlenecks. Everything else is negotiable.

Really? I don’t see many British men tucking in their polo shirts these days – and do you know what? I wouldn’t want to. It’s a shirt that’s made to drape, at least in this nation’s eyes, and drape is what we let it do.

Of course the Americans have Texas to contend with, and it comes up more than once on their clothing list – so a ten gallon hat and cowboy boots are okay, but a hoodie is only acceptable occasionally? Somebody should tell those boys William and Harry – you know the ones, the heirs to the British throne … the ones who actually play polo, not just wear the shirts?

So maybe the rules are slightly different depending on your accent, but the basic guideline is the same – high fashion only works if you really work it, and most of us don’t have the budget or the body. Stick to the classics, buy good casual clothing and keep it clean and neat and you’ll get by.

Hoodies don’t work for everyone. Your gran might not be comfortable in something that she associates with heavyweight fighters clambering into the ring for televised boxing matches. Your teenage nephew may have strong ideas about what a hoodie should look like: and given how easily kids become mocking or outright hostile if clothing doesn’t fit perfectly into the current style, he may be right to worry.

On the other hand, a sweatshirt is uncontroversial. From cute girls, to crusty elders, it’s eminently wearable. It’s warm and comfortable and the elasticated cuffs and snug hem ensure that cold winds don’t invade the garment to cause chills and discomfort. But because it’s not bulky, a sweatshirt still looks good under a jacket or fleece. And when you head indoors, the weave radiates heat away from your body so that you can cool down rapidly, unlike a wool sweater that can remain uncomfortably warm and sweatily prickly.

When choosing a sweatshirt for another, the colour is really vital. Blue works for almost everyone; black is good for teenagers and if you’re confident about colour, you can push the boat out and choose something that enriches winter skin, such as a rosy red shade for pale redheads, a rich tangerine for brunettes or even a fuchsia shade for those with greying hair.

In the past year, Indian shoppers have got into buying clothing online in a big way. The division by gender is around 70% male to 30% female, with retailers focusing on social media to reach out to women who are a growth market for all forms of retail in India. Global clothing companies are rushing to get into this market, especially to bring their retail expertise to many customers who live in small towns, villages and the hamlets or rural India.

Casual apparel has the second highest seller online in India: ahead of books and DVDs. India’s ‘internet population’ has moved into e-commerce with ease: the nation has around 10 million online shoppers, a market that is growing at 40-45%, compared to the global rate of around 8-10% growth. eBay India retails a garment every seven minutes – many of which are sports shoes and clothing with Adidas and Reebok featuring highly in the popularity stakes.

Children’s wear is also a rapidly growing market with Indian mums investing in clothes and shoes, along with feeding bottles, buggies and toys. Menswear is growing too:one company that sells work shirts at under 900 rupees each has sold 2,500 shirts since it launched in August and is expecting to sell 5,000 collared shirts a month in 2012.

Personalised workout clothing is a big seller, with monogrammed hoodies and polo-shirts being a regular purchase by individuals and as presents or to commemorate work events such as promotions or anniversaries, which are popular celebrations in Indian culture.

Budgeting for clothes is difficult: one person may feel it’s worth spending half their income on new garments, another may think that less than 10% of their take-home money should go on clothing. For some people it’s important to have a lot of clothes and always look in fashion – if you work in retail or the media, for example, it’s really vital to look like you have a fashion pulse! For a geek, a classic wardrobe of jeans, T-shirts and a polo-shirt for visits to grandparents may be the entire outlay … and that’s cool too.

What’s important is that clothing be durable, comfortable and pleasant. That means pleasant to wear and pleasant for those who see you wearing it: saggy, baggy, stained and smelly are not pleasant, so clothes that lose shape, hold stains and odours or are too expensive or complicated to launder really don’t fit with a limited budget. Cotton clothing, whether in the form of smart collared shirts or simple plain T-shirts, is an ideal choice.

Cotton garments are easy to wear and always easy to wash and dry – whether you’re a fashionista who presses everything with starch or a casual dude who simply takes stuff off the line or airer and wears it, creases and all.

Cotton clothes are also very versatile. Shirts can be teamed with contrasting T-shirts to get a wider range of clothing choices and hoodies can be worn over T-shirts to give a soft, relaxed feel.

Hollister has become synonymous with twilight retailing: and teenagers seem to love buying casual clothing in such dark conditions that they don’t actually know what colour their new garments are until they’ve got them out of the store. According to the Daily Mail, parents are complaining about not being able to see the true colour or the price of what they’re buying, and even of losing track of their teenagers in the store.

The ‘greeters’ whose six packs are on display even if there is snow on the ground are also viewed with suspicion by some parents who feel they are tacky or maybe even that the young men are being exploited.

Even so, the Hollister experience seems to be a popular one, so what can parents learn from it about teenagers and shopping?

1. Casual clothing needs special focus – because teenagers spend most of their time in jeans, joggers, hoodies and trainers, these, not party outfits, are the focus of their attention, and the party atmosphere of Hollister can make them feel they are getting more for their money. To get your teen to shop in less expensive outlets, or even online, arrange for one of their friends to come round, let them play loud music and lay on pizza, snacks and multi-player gaming in between bouts of online clothing browsing. This makes them much more likely to engage with the idea
2. Colours matter – Hollister are coy about the number of returns they receive but it does seem to be the one part of the shopping process that disconcerts teens. Point out that online shopping allows teens to look at all the colours, sizes and options, to do comparison shopping and even to google potential purchases and see reviews on their wearability. This encourages a picky shopper to realise that they can spend as long as they like debating a black T-shirt versus a red one, online but in the shop it gets annoying to family and friends!
3. Feed the senses – Hollister spray perfume around their shop and on their customers to make the experience memorable. Do the same for your teen shoppers by squirting the room with their body spray before they start shopping – believe it or not, psychologists say that a favourite scent can  prejudice us in favour of an experience by up to 46%.

This is the time of year when parents start asking who is going to visit whom for Christmas. It’s a real snake pit: do you go to your own parents or instead stay with your boyfriend/girlfriend’s family? If you’re a senior, do you ask the kids to visit again, or admit that you’d rather stay with a friend/take a cruise/sit at home in your underwear and watch TV?

In any case, one feature of the holidays will be photos – the obligatory family picture that gets filed in the family album. What do you wear for the photo – and if you have little children, what should they wear?

1.    Begin by deciding on the basic theme of the photo – when it will be taken and does that mean it will be casual or dressy? If it’s over the dining table, take the photo at the beginning of the meal not the end, when gravy splashes and family bickering may have spoilt the tablecloth and the mood.
2.    Browse online to pick some colour themes: black and white look a bit like a funeral but festive red and green don’t suit everyone. If you can suggest a basic colour scheme to everybody who will be in the photo, it’s a nicer way of reminding them to dress up than just asking them to look smart! If your family are totally non-cooperative, ordering individually monogrammed Christmas polo shirts or hoodies for everyone can be one way to get them to look reasonable in the photo album!
3.    Remember that whether shopping or appearing in photos, children have short attention spans so get everything ready in advance, and rather than dragging them round the shops, put together some outfits online and then let them choose from the items you’ve already pre-selected: it’s a two minute job and nobody gets stressed.
4.    Get everybody to try on their clothes for the photo well in advance of the day, so that tears or stains, grubby collars or outgrown items can all be dealt with before they become a last-minute crisis.

A recent show at Imperial College, London offered vanishing dresses (using a blend of polymers that dissolve when exposed to H2O), hoodies that actually clean the air as you walk through it, thus leaving the street cleaner than when you found it, and special underwear that makes you fitter.

Within five years we may see full-body compression underwear that allows even ordinary gym goers to run faster, lift more and punch more strongly. Also on the cards is a sports bra that shapes itself to the wearer, and most interestingly to many women, ‘clever’ undies that use the body’s own heat to generate tiny electrical pulses that activate the muscles so that you become slimmer the more you wear the garment. This technology could also be used in socks to help frequent flyers and those who stand all day, by returning blood to the upper parts of the body, thus reducing the risk of clots, thrombosis and varicose veins.

Photo-catalytic clothing is already being tested. It involves cotton clothing treated with a chemical layer that reacts with light to break up water in the air and create radical molecules that neutralise pollution – fitted into the jogging bottoms of running groups or the jackets of street workers this layer could actually make our cities cleaner and safer at no cost to us.

England fly-half Jonny Wilkinson may be the only bright note on the current England squad. Not only is his behaviour impeccable, his clothing has become a focus of attention too: he’s working with his brother to create a fashion brand that combines sports clothing with smart casual elements.

The line is called Fineside and is particularly designed to work with the mesomorph body type that the Wilkinson brothers typify: large boned and well-muscled with a low waist and chunky legs. This body type generally looks good in casual clothing as long as it’s not too tight-fitting. Polo-shirts and tops with a back pleat work well for men, and for women, wearing a hoody with a zip front can help give a defined shape to the larger-boned woman.

Casual clothing also works well with the modern lifestyle that moves from office to gym to bar via a commute and maybe a noodle lunch. Picking clothing with flat seams that’s crease-resistant and can be dressed up or down quickly is a great way to making the urban active lifestyle more streamlined.