I had thought for years I was unable to donate within the general population (one of those obscure things in the guidelines), but when I made a directed donation for my mom they ran me through the third degree and it turned out I could donate. I've been donating fairly regularly ever since, but my doctor has advised me to reduce the frequency because it's caused quite a bit of scarring on my arms, which he says could lead to problems as I get older (possible reduction in blood flow, difficulty in health professionals starting an IV in preferred veins, etc.). I tried the double-red route, but had some ill effects afterward, so I'm back to the whole blood donation.

So while I still donate, the frequency has dropped. The coolest thing about it is that when you give whole blood, most of the time that ends up helping several people, as they spin the blood out to its components and give the components where they are needed.