Start a Collection
If you don’t collect some sort of souvenir when you travel, I highly suggest you start. It doesn’t have to be expensive, maybe a mug or a magnet (besides, it’s more fun to spend the money on something else, like a Mai Tai). Some people think they’re corny. I think they’re seriously awesome.
Unlike pictures and memories, sometimes it’s nice to have a tangible reminder of all the fun you had on your adventures. I collect postcards—I write down my favorite memory from the trip on the back and ask everyone I was with to sign it. That way, ten, twenty, fifty years from, I can look back through them and remember all the fun I had (and hopefully inspire myself to take another trip!).