Like gloves, scarves, car keys, spectacles ... TV remotes and the bits of paper you have jotted down the entry codes for your video games, nail clippers are always there when you don't want them but never when you do. The logical solution to this, I suppose, would be to keep them permanently in a dedicated nail-clipper drawer. But it never works in practice, partly because you can never be arsed to replace them once you've finished, and partly because you secretly want to guarantee yourself more time-wasting the next time round.