My ferritin levels are quite high, and anecdotally I started feeling better after I started donating blood. It's a win-win, so I donate as much as I can (which is every 3 months here).

They've also started sending a text message every time my blood has been used to help someone, which is one of the best warm and fuzzy feelings ever, that knowledge that you've made a genuine difference in some other person's life.