See what you're meant to do when you have a mid-life crisis is buy a fast car aren't you? Well I've always had fast cars. It's not that. It's the fear that you're past your best. It's the fear that the stuff you've done in the past is your best work.
It's very important to write things down instantly or you can lose the way you were thinking out a line. I have a rule that if I wake up at 3 in the morning and think of something I write it down. I can't wait until morning - it'll be gone.