That's more or less true in the photographic sense, since most items are replaceable at a functional level. I have a couple of cameras--my Nikon F and a now-retired Agfa Silette--that I would be rather loathe to sell at any reasonable price since they were given to me by my dad many years ago and so have some sentimental value for me.
Originally Posted by David Brown
But, beyond that, I'd have to go with my meter (A Gossen Luna Pro F). I use it with all of my cameras, whether they have a built-in meter or not, and it's been pretty dependable.