Which clothes in your wardrobe are you actually wearing? According to professional wardrobe organisers, the answer is surprisingly few - about 20 per cent. The remaining 80 per cent of our clothes hang there untouched.

For all kinds of reasons, it's very easy to end up with a wardrobe full of things you don't wear. But keeping clothes that don't do you sterling service is a mistake. You have to maintain them, you have to insure them, you have to store the damn things and be responsible for them.

If you're not sure about this concept, consider for a moment that every square inch of your house costs you money. Look at how much square footage of your precious property they are taking up. What is that worth to you in real terms? My house in rural France is worth 1,000 euros per square metre. In the South-East of England, your house might be worth £265 per SQUARE FOOT. Seriously, how much of that precious space do you want to devote to clothes?

Apart from creating extra space, working on the basis that every woman needs a wardrobe that actually works for her, sorting out the sheep from the goats among your clothing has other advantages.

* You will no longer have days when you have 'nothing to wear'.

* Everything in your wardrobe will fit and flatter you.

* Dressing in the morning will be easier and stress-free because, by and large, everything will go together.

Sort it out

Step one to discovering what works in your wardrobe and what doesn't, is to find out what you're actually wearing right now, and you'll probably have to do this at least twice (once for summer and once for winter, or even more if you divide your clothes by extra seasons). For this exercise, you'll need the following:

* A clothes rail. Place this in the spare room/adult child's room/anywhere dry and safe where your hangable clothes can be stored for a while.

* Two brightly coloured ribbons. Tie these at the right-hand end of the hanging rail in your wardrobe. They should be different colours and loose enough so that you can slide them up and down the rail.

* Two long wardrobe shelves, cleared of stuff, or two large cardboard boxes for storing foldable clothes. Label them 1 and 2.

Over the course of the next two weeks, whenever you wear a hangable garment, replace it on the rail to the right of the first ribbon, moving the ribbon along as necessary (wash or dry-clean garments as you go along, as you would normally, obviously - don't put them away dirty). Likewise, whenever you use a foldable item such as knickers, t-shirts, bras, jeans and so on, replace it on the first set-aside shelf, or in the first cardboard box.

If you find you use an item more than once, place it to the right of the second ribbon, or in the second box - these designate your 'frequently used items'.

After two weeks, take a look at the clothes that you've actually worn. Why are you wearing them? Chances are, they fulfil a number of criteria:

* They fit you.

* They're comfortable.

* They're practical for your lifestyle.

* You like them.

* They may also flatter you, though not necessarily - they may just be all you've got.

Now make some notes

1: If these clothes fit you, make a note of the size. If, in all honesty, they're too big or too small but you're wearing them because you have nothing else, give this step a miss.

2: If they're comfortable, ask yourself why - is there a generosity of cut, a particular length of sleeve, a height to the waistband that you favour? Are you looking at a coat with a shoulderline that goes over everything else or is the right length for the car? Are the knickers ones which actually hold your buttocks in place rather than cheese-wiring you into submission? If so, note it down so that you can duplicate these buys. For instance, I no longer wear short tees or vests - only long ones that don't come untucked when I bend or crouch.

3: If they're practical for your lifestyle, try to analyse why. Does the colour go with your other things? Is the fabric? Is it that they're patterned and don't show the dirt? Is it because they're easy to maintain? Two years ago, I switched all my foundation pieces to the colour navy, with occasional forays into black or charcoal. I lead a dirty life of dog walks, woodburners, gardening and cooking, and navy is a good, practical colour that doesn't show the muck but still feels quite smart. 

4: If you like them, again try to analyse why. Be specific - this blouse makes you feel sexy, this dress makes you look taller, you can run in these heels. Your particular likes and dislikes may be nothing to do with 'fashion'. 

5: If they flatter you, you'll know from other people's reactions as well as your own. Ask for guidance. Is this just the right neckline for you, for instance? Is the skirt length just right for showing off your calves? Does the colour make your complexion sing? Define exactly what it is that's flattering about this garment and reproduce it.

Now list each of the five categories above, so that you can give the rest of your clothing a score out of five.

Finally, take all the clothes you didn't wear out of the wardrobe and hang them on the rail in the spare room. Ditto with the folding clothes you didn't wear. Store them on the spare bed for now, or swap over your cardboard boxes and put those in the spare room. These unworn clothes now have a two-week reprieve before you analyse their wardrobe value and consider getting shot of them. You might be surprised at how few trips you actually make to that spare room.

There is a great video on the Guardian site that I urge you all to watch. It's about how to chuck out your unwanted clothes PROPERLY so that they don't end up in landfill.

As the presenter points out, women are the worst culprits by far when it comes to owning (and then having to throw away) useless garments. But even if you give your old clothes to charity, their usefulness varies. 

Good stuff

1 Denim. Any size, style or colour - this will find a home on the backs or the legs of workers in the third world. Denim is tough stuff, with years of life left in it long after its fashion possibilities have faded. 

2 Tights. Their Lycra content makes them invaluable as bandages in countries like Ethiopia. Send to:

Ethiopia Tights Appeal Tightsplease

2nd Floor, Albion Court

18-20 Frederick Street

Hockley, Birmingham

B1 3HE

3 Bras. British bras are well-made and engineered. Even when broken, they're valuable. But the presenter says you may need to educate charity shops as to their usefulness.

4 Towels. Animal charities can always use old towels, no matter how faded and threadbare. Personally, I use up my old, and other people's old, towels for the dog. 

I have been calculating my fashion expenditure this year and frankly, it is looking parlous.

Not that I spend much in a  good year. My personal spending allowance used to be £15 a month, from which I have to get all my clothes, makeup, books, CDs, DVDs, etc. 

But what with the recession and all, we cut it this year to £10, and that is a serious difference. For £15 I could always get something, but with postage, as I have to buy most of my things mail-order, £10 is a serious restriction - I am down to absolute necessities. 

When it comes to clothes, I don't count those I buy at the supermarket as my personal allowance because those are part of the normal shopping budget - if I want something, then something else on the list has to go, such as meat. But there hasn't been a deal of that this year either, having cut the food budget from 140 euros to 50. 

This year, my clothing expenditure has been:

* Boden taupe leaf-print wrap dress (Ebay, 6.73). Worn maybe once, so crap has the summer been...

* Bootcut denim leggings from BHS (Ebay, 7 quid - to replace a pair that fell apart). Wearing these to death.

* Ugg-style suede boots with a 'cardi' trim (Ebay, 7 quid - to replace a pair that fell apart). Haven't received them yet - this is me getting ready for winter.

* Navy Crocs (Ebay, 21 quid) on the podiatrist's orders. Sent to the Cayman Islands by error, so I'm still waiting for these too.

From the supermarket:

* Nine pairs of men's jockey shorts (Lidl, 9 euros) to replace my falling-apart knickers (and SO much more comfortable than women's underwear).

* Two cotton vests (Lidl, 3 euros) that are actually long enough to go over my jeans.

* A pair of Trex walking shoes for hiking (Lidl, 14 euros). 

That's it. About £65 all told, and most of it to replace items that had expired. 

In the earlier part of the year, I spent all my personal allowance on medicines and supplements for my cat Lucy before she died; in April the money went on my sister's birthday present; and other than that, I've spent it on books - this month, works by the Dalai Lama and Taro Gold (thank heavens, once again, for Amazon resellers, where you can pick a book up for a penny).

Meanwhile, I have actually sold a bunch of my vintage stuff for 200 euros, so that makes me feel very virtuous - more clothes going out than coming in. Among them were:

* A 1920s black lace and velvet dress that my husband bought me. (It was beautiful and I literally cried at parting with it, but I couldn't see me ever wearing it again.)

* A bright turquoise 1950s velvet coat (I wear an almost identical burgundy one).

* A black lace blouse from M&S (I wear another, almost identical one). 

* An art-to-wear jacket from a modern designer (didn't suit me). 

* A white ribbonwork cardigan with scalloped hem and sleeves (I wear one of the two others...). 

* A late 1930s crimson rayon chiffon dress with crochet sleeves (never worn it, too fat for it). 

* A Jean Muir jacket that I wore precisely once (fits my old life, not this one). 

As an upside, the women who bought the clothes looked far better in them than I did, so I know they're going to good homes. 

It can be hard to part with things you love, but once they're gone, I find you don't think about them much. And you have to be realistic about the kind of life you lead - many of these clothes are my old life. When I eat out once or twice a year, there is no point in hanging on to 20 evening gowns, and I would rather have some more money at the supermarket, or money to spend on books than have something beautiful to gaze at in the wardrobe. 

I found a nice little article on wardrobe decluttering the other day, so thought I'd share it with you.

It's about what to do with your cast-offs - that big pile of rejects that you assemble at the end of a long day of riffling through your wardrobe and throwing out. 

There are, of course, several different reasons that you might want to throw something out, but you can take an eco-friendly approach to what to do about it. 

If your clothes don't fit because they're too small, and you're really not going to lose the weight, then think about selling them on Ebay, swapping them with your friends or simply giving them away. Care2connect gives a list of organisations that would be grateful for your cast-offs and although these don't apply to European readers, we can usually head for the charity shop or an Emmaus drop-off point. I get together with my girlfriends about once a quarter to swap clothes and those that no-one wants are taken to Emmaus, where they're given to poor local families. 

If your clothes don't fit because they're too large, then consider having the good ones altered and discard the rest as above. Particularly if you've lost weight, don't keep overlarge clothes hanging around the house - it's way too much temptation. 

2 - it's out of date.

It depends on how out of date and in what way, but there might be a possibility of salvage here. If a piece is of good quality or a favourite but the collar or shoulders are wrong, it can be worth having it retailored to a more contemporary style. Only do this, however, if the item's really worth it - a good wool suit, say, or a coat - because otherwise it's usually more cost-effective to get rid of it and buy a new one. Have the job done professionally - resetting a shoulder, for instance, is a job well out of the skills range of the average home sewer.

3 - you're bored with it.

Sometimes you do get sick of seeing the same old thing and it can be hard to get excited about an item you've worn a thousand times. Here is where it's handy if you're handy - if you can find some way of altering a garment yourself. My favourite thing is dyeing. Back in the days when I was an impoverished student, I used to buy all manner of charity-shop clothes in awful colours and have them dyed black at Sketchley's dry cleaners. I'd then add new trims and buttons and voila - completely different.

Although it's more difficult to get clothes professionally dyed these days, you can still do lightweight items yourself in the washing machine. I use Dylon dye, at twice the strength recommended, and my towels, sofa covers and sheets also all get revamped every so often, along with jeans and t-shirts. For a more complicated approach, I use the shibori dye technique, but I'll leave a description of that for another time.

Adding new trim or a fake-fur collar or new buttons to a cardigan or jacket can completely change its appearance if the basic garment is sound - you can find these in notions departments. And while you're in town, why not head for the library and see if you can find one of those books about revamping your clothes that were all the rage in the 1980s? Some of the ideas seem laughable now, but others, such as leather elbow patches, still work. I'm willing to place a bet that patching your jeans with brightly coloured iron-ons as we all did in the 70s will once again become the rage in the economic downturn.

4 - it's past its best.

If that means that it's frankly shabby but you like it, consider giving it one pass through the dyebath - a good dye job can cover a lot of fading and give you an extra year's wear on a garment. If it really is too knackered, then either pension it off for rough work, give it away or think about recycling it in some way. In this house, all our dusters and floor clothes are made from old pyjamas and t-shirts, while old jumpers get felted in the machine and cut out for patchwork (or given to my friend M to make bags with). Even if you don't do craft yourself, you may find a local craft group will be grateful for your old fabrics, especially anything in lightweight cotton, which quilters love to work with.