I normally do this on the first of April, or the weekend closest to it, but this year's been so cold and dark, and spring so late, that I left it for the first proper spring day instead. For some reason this year (global warming?), we seemed to switch directly from winter to summer without really going through spring at all, and at the weekend, temperatures rose dramatically.

Changing over your house between winter and summer is a very wabi-sabi thing to do because it acknowledges the turn of the season and reflects the fact that you use your home in different ways in winter than in summer. Making dual use of your space in this way also makes it feel twice the size - like you have your very own holiday home.

In winter, you need your house to be more 'yang' - warmer, brighter colours and rich textures that comfort and cheer you through the cold months. You want to snuggle down and shut out the outside world.

But in summer, you want the opposite - cool, Yin colours, smooth fabrics such as linen, and lots of light and air. You want to open the windows and doors whenever possible, and embrace the view, which - if you're lucky - will be changing gradually to green.

The absolute best way to accomplish a changeover is to have a seldom-occupied spare room where you can keep your off-season items. Then in spring, and in reverse in autumn, you can make the switch easily.

The major change I always make is to take the winter curtains down. Who on earth wants heavy velvet drapes in summer? In winter, they're a godsend, because this house is on a hill and very exposed, but their fabric, and their rich colours of red and pink and peach seem stifling and stuffy when the weather turns. We're not overlooked, so I sometimes don't bother with curtains at all in summer, preferring to allow the light to flood in, but sometimes I switch to white lace, or a set of curtains I made from old cream hemp sheets (very House and Garden). These are useful if the weather gets really hot, as you can draw them to keep the heat out and diffuse the strong light to a soft creamy white. Off-season curtains are stored in flatpacks in the spare room.

I gave up rugs a year or two ago and I loathe fitted carpet in any case (too insanitary and difficult to clean). We only have hard floors now - terracotta, wood parquet, cork or hard vinyl tile, depending on which room you're in. But in the days when we still had rugs, I would roll them up and put them away in spring. If you can't do this for reasons of space, consider turning them over instead, if they have a jute backing, for a summery look, then flip them back to the pile side for winter.

The changeover idea works best if your furniture has slipcovers rather than - or in addition to - permanent upholstery. When we bought our sofa, we bought two sets of loose covers, so in winter we have an aquamarine and navy blue scheme, then in summer we switch to yellow and aquamarine. The sofa is a large piece of furniture and this change of covering alters the whole ambiance of the room.

If your furniture is close-covered, you could have loose covers made for it for summer, or think about using summer throws in fabrics like linen or cotton, which will be cooler to sit on than Dralon, leather or velvet. A set of matching throws in a cool colour like primrose, cream or pale blue can take the visual heat out of any colour scheme. Put any loose cushions away for summer, too, for a cleaner, more spare look in the summer months.

Also consider moving your furniture about between summer and winter. In winter, you probably want your living-room furniture clustered around the fireplace, if you have one, but in summer, there's no sense in this if the fire isn't actually lit. Think instead about moving the furniture closer to the windows to make the most of the light, and creating more space between individual pieces to allow air to circulate.

Change your lightbulbs over too. In winter, in this dark house, I use 100w or 60w bulbs wherever possible, but in summer 40w is more than enough because there is so much more light from outside.

Finally, think about changing over your wall art with the season. I use obi sashes and kimonos on poles, which are readily interchangeable. I swap a heavy purple kimono for a gold one in summer, and black, red and orange obis for ones in shades of silver, pale blue and cream. Even though the mirrors and framed art remain basically the same, the 'feel' of the room is altered dramatically just by changing a few items.

Wabi-sabi arose from Zen Buddhism but it enables you to live a simpler and less-cluttered life whatever your situation or beliefs. Earlier I wrote about the tokonoma, a special alcove or area that you can have in a room as a focal point, but here I'll deal with surfaces.

In wabi-sabi, it's very basic: you keep your surfaces clear, and if you can't, you limit the number of things on them to three. Just follow this 'rule' and you'll find it all comes together easily.

To start, look around your typical living room and count how many surfaces there are. In mine, which is a living-dining room, there are eight:

* a centrally placed sideboard used as a room divider

* a sideboard in one corner

* a coffee table

* a dining table

* a marble-topped buffet running along one wall

* and three deep windowsills (this is a French house and the windows open inwards)

All of them just asking to get filled up with tat.

The marble-top buffet had all the CDs and DVDs on top of it, which was fine as long as they were neatly arranged in their storage units. Problem is, they never were - they were stacked up 10 deep, constantly waiting to be refiled. My sideboards seemed to have the habit of collecting whatever was meant to be stored in their drawers and cupboards, while my coffee table, like many people's, rather defied description, piled high with books, magazines, coffee cups, wine bottles and God-knows-what else.

All this is by way of saying that I am by no means naturally tidy, nor clean, and that my approach to housekeeping is - um - relaxed, to say the least. Nor do I get much help from the DH in this, as he simply doesn't notice mess.

My biggest sin, though, was one committed by many of us - cluttering the windowsills. Which of us doesn't want more light in our rooms? Certainly not me. My house is old, with thick walls and tiny windows and every scrap of light is precious. Why, then, did I persist in putting pot plants and flower arrangements and candles and wotnot on my windowsills? I suppose I thought it added character. Well it doesn't.

As a first step to wabi-sabi, CLEAR your windowsills. Don't put anything there - not lamps, not ornaments, not candles (and matches and incense-stick holders...). It will take a couple of weeks to get used to how bare this looks, but once you get your eye in, it looks completely natural - you will benefit enormously from the light, and it also makes the windows much easier to both clean and open. Whatever you do from now on, don't block your windows. (For purists, this is in fact more of a Zen approach than Wabi-sabi, but we'll go into that another time.)

From your windows, progress outwards into the room. If there's one piece of furniture that you look OVER as you enter the room, this is the next important thing to keep clear. In my case, it's a green-painted sideboard to the left of the door as you enter the room.

In former days, this usually had three wooden bowls on it. I loved them, but somehow they always collected companions - unpaid bills, bank statements, letters to be posted, gloves, the dog lead. Now I work hard to keep that sideboard completely empty even if I don't have time for anything else. Gloves go in the drawers in the front of it. The dog lead's been given a hook by the door. If my husband dumps a bill or a letter on this sideboard, I immediately remove it to the dining table where it's less noticeable (the dining table remains a bit of a disaster area, as I do my beadwork on it, but nothing in life is perfect).

For many people, the coffee table is just a clutter magnet, so buying a table with two layers is a good move. The detritus that builds up on the top shelf can easily be cleared to the lower shelf each day and then you can deal with the whole mess later in the week. Be practical about this if housework isn't your idea of a good time. A glass top is all very well, but it shows every fingermark and you can still see all the rubbish underneath, whereas if you choose a natural wood finish that is not highly polished, or a white or grey distressed finish, you can hide a multitude of sins. We don't have a two-layer table, though I aspire to one, but we have one with two sliding sections, made by my husband's father, which enables us to hide the remotes, etc.

For surfaces against walls, such as sideboards, console tables or tallboys, you can afford to be less strict. These surfaces are usually not USED as such, but they are in your sightline as you enter a room, or as you sit on the soft furnishings. If you lack the discipline to keep these completely clear, try to limit your items to three in number - for instance a lamp, an ornament you really love, and a flower arrangement that reflects the season. That gives you a simple still-life that adds texture, colour and light to a room without overwhelming it.

In my own home, the clutter on the marble-top unit required the most thought. The problem was really lack of storage, and this was dealt with by the DH taking all our CDs and ripping them into I-Tunes, then discarding the ones that we never played (let's face it, with most albums you only really love a few tracks, not the whole thing). This freed up about a third of the space in the CD racks, leaving plenty of room for a 'refile' section into which I can quickly pop any loose CDs prior to refiling them properly.

Voila, clean surfaces that are easy to dust and wipe down without having to move anything - and that means they get cleaned more often.

Wabi-sabi, of course, arose in Japan, so to apply it in your home, it helps to know a little about what a traditional Japanese house looks like, though very few Japanese still live in them.

A traditional Japanese house is modular and most of the wall space is taken up either by floor-to-ceiling built-in furniture that stores the family's clothes, bedding, etc, or by sliding doors. The doors, called fusuma, can be opened up to create one big space, or closed to create smaller spaces.

This modular construction has affected the way rooms are decorated. You can't hang paintings on a wall of storage furniture, and large sliding doors tend to look rather boring left as they are. Therefore the Japanese paint their doors, as you can see at right, rather than hanging paintings on the walls, while the walls are left entirely empty - no pictures, no paintings, no photos of loved ones.

This can leave an interior looking very bare to a Western eye, which is more accustomed to having something - or preferably lots of things - to look at, but the Japanese attitude to art is different. They don't keep their things on permanent display. Instead, they take them out and use them and put them away again.

As an analogy, think of how you take out the Christmas decorations each year, and how pleased you are to see them and how nice the living room looks when the decorations are up. Think too of how bare the room looks without them when you put them away again. But very quickly your eye adjusts to it and you get used to the room looking as it usually does.

In order to have somewhere to display art, the Japanese came up with an alcove known as the tokonoma. This is based on the shrine found in Zen temples, which would contain a statue of Buddha, with offerings and candles etc. The tokonoma is basically just one corner of the room set aside. Sometimes it has a rough wood pillar at the open corner, and the floor is often raised like a dais.

Here, the Japanese display a hanging scroll with calligraphy and perhaps a painting relevant to the season, and an ikebana flower arrangement. Sometimes there might be a bowl or a statue or a bonsai tree, but usually there are no more than three things. They then change these items on a monthly, weekly or daily basis.

The tokonoma idea is one that can easily be incorporated into a Western home, and here's how to do it.

Remove all your paintings, pictures, wall art and photographs from a room, and set aside one area - preferably a corner. You could choose to paint this area a slightly different colour from the rest of the wall, or mark it off in paint like a frame. Place a table, or buffet or a chest of drawers there, and on it place a vase of flowers picked from the garden. Behind, hang your favourite painting or photograph. That's it - nothing else.

Now look at it. When it's the only thing in the room to fix on, you'll find you pay much more attention to it. But after a week or a few weeks, you'll also realise that you're looking at it less. This is the time to change the art, just as you would change the flowers as they dry and wither.

Try this approach at home and see how you get on - by cycling the things you own, you'll generally find that you need fewer things but that you build a deeper appreciation of each one individually.