Gosh! I am amazed that so many people have got old compasses.
Mine only seem to last 2-3 years before they get a bubble, though, to be fair, they always get a lot of use. And yes, they have all been good quality Silva compasses. What's the secret of keeping them so long?
Otherwise, I think my steel thermos flask, a Patagonia fleece (bought in a sale) and my whistle might be the oldest things still in use (1988), although I have probably got an ancient smelly helly from 1974 or so.