The cupboard under the sink looks like a cube and behaves like an obstacle course. A waste trap, a run of pipes, a washing machine hose and sometimes a food waste unit occupy the middle of it. Every organiser that fails down there failed because someone measured the cupboard rather than the space around the plumbing.

Map the obstruction before you buy

Open the doors and note where the pipework sits, how far it projects forward and how much clear floor lies either side. Most sink units end up with two usable columns and a shallow strip at the front. Those columns, not the cabinet width, are what you are shopping for.

Tall and narrow beats big and square

A large square tub cannot pass the trap, so it lives half empty in one corner. Two slim bins that slide either side of the pipes hold more in practice and can be lifted out one handed. Slim under-sink bins of the sort listed at https://mdesign-us.com/ are sized for exactly this problem, but check the internal height against your pipe run before ordering more than one.

Leaks are the reason to keep things off the floor

Slow leaks at a compression joint are common and often invisible until cardboard turns soft. Keep everything in washable plastic or metal, not cardboard, and leave the floor of the cupboard visible so you can spot damp. A small tray under the trap turns a leak into a puddle you notice rather than a swollen carcass base.

Chemicals need a rule of their own

Bleach, oven cleaner and drain unblocker should not sit above open packets, cloths or anything you eat from. Keep them in one closed bin, upright, with the caps facing you. If there are small children in the house, this cupboard needs a catch on the door regardless of how tidy the bins are.

Use the door, but check the swing

Door-mounted racks work well for washing-up liquid, sponges and gloves, and they use space nothing else can. Measure how far the rack projects and whether it will clash with the trap or the shelf when the door closes. On thin doors, screw fixings are better than adhesive, because a loaded rack pulls straight down on a vertical surface.

• Measure the clear width either side of the trap, not the cabinet
• Keep the cupboard floor visible so leaks show early
• Store cleaners upright and separately from cloths and food items
• Choose bins with handles you can grip whilst kneeling
• Leave a gap at the front so the door closes without contact

Fewer bottles is the real upgrade

Most sink cupboards are full because they hold six half-used cleaners bought for different rooms. Two general cleaners and a bathroom product will handle almost everything, and clearing the rest usually frees more room than any organiser. Sort first, then buy bins for what remains.