After undergrad, I was more or less not learning anything for 4-5 years. One day I got asked how to do integration by parts and I completely forgot. I felt so terrible, I went back to grad school (for math, no less!) Now I am about to get out again, and I'm terrified I'm going to lose it all without adequate mental exercise. I can read papers and tinker all day, but I'm concerned it'll all slip away again and I will end up a total drooling moron with no economic utility whatsoever. I'm trying to figure out how I can do R&D, keep math skills sharp, AND keep a job without declining into a turd. Yeah, you can say "oh, just study daily", ... but, realistically, without the fear of bad grades or some other fear, I'm only going to be motivated 20% of the time to really dig down into the math. You can laugh at me now and say I'm an idiot already, but Obama's going to rob from you and give it to me if you don't give some decent tips on how not to be even more of an idiot... so you can put your smug supremacy away. Don't be so certain I and my idiot friends won't vote for some guy who promises to give me hand-outs. Have any of you managed to stay sharp?