An allied problem is not being able to remember whether you have a thing or not. You can spend ages looking, not find it, and still not know whether it's hiding, or was only ever on a wish list.
And then there's finding things and wondering what the hell they are and how and why you got them. And finding things bought for that urgent and important job you've quite forgotten about – and which has remained ignored for years.
And finding stuff you forgot you didn't have – or, rather, finding the empty space in the multi-compartment box which should hold the screw you need, but forgot to buy, ages ago, after you used your last one.