Don’t collect DVDs and movie tickets. Collect film reviews you wrote yourself, no matter how short and shallow.
Don’t collect books that will just gather dust in the shelves. Collect the ideas you developed after you read them.
Don’t collect the pictures you took or posed for while you hung out with friends. Collect anecdotes.
Don’t collect things. Collect memories. Yes, they are fickle, and they get distorted through time. But they weathered and shaped by your own ever-changing view of the world.