The cupboard under the stairs starts out with a sensible purpose, perhaps for coats or the vacuum cleaner. Over the years it becomes the place where anything without a home is quietly put. Boxes of cables, spare bulbs, old umbrellas, board games and a broken lamp join the pile. It is time to take everything out and start again.
Empty the cupboard completely, even the parts at the very back where the roof slopes down. You may need a torch to see into the corners. Lay everything out in the hall or on the floor of the nearest room. Sweep or vacuum the space, and wipe down the shelves if there are any. An empty cupboard shows you how much room you really have.
Sorting into groups
Sort the items into groups: cleaning things, coats and shoes, tools, seasonal items, and things that belong somewhere else. You will often find that half of it does not belong here at all. Books, toys and paperwork are common strays. Return them to their proper rooms straight away. Anything broken or unwanted goes into a bag for the tip or the charity shop.
Think about how you use the cupboard day to day. Things you need often, such as the vacuum cleaner or the ironing board, should be at the front and easy to reach. Items you use rarely, like suitcases or decorations, can go at the back or on the higher part. Heavy items belong on the floor, and light things on shelves.
Use the door and the walls to gain space. A row of hooks on the back of the door holds bags, brushes and aprons. A small shelf unit or a stack of baskets makes the most of the height. Labelled boxes help you find what you need without emptying half the cupboard.
Leave a gap in the middle or at the front so that you can walk in or reach past things. A cupboard packed to the roof soon becomes impossible again. Check it once in a while, perhaps when the clocks change. If something new goes in, something else should come out. That way it stays useful for years without another big clear-out.