What? No, really, this seems like a strange question. You'll learn and forget all sorts of things in your life. The things you remember, the things you need to

What? No, really, this seems like a strange question. You'll learn and forget all sorts of things in your life. The things you remember, the things you need to remember, are the things you use all the time. Outside of exam halls and ridiculous interviews, you almost always have a search engine. Knowing how to use it is 50% of professional development. (Note: I'm not saying don't learn things. Of course you need to learn syntax and how stuff works and ... well, there's huge amounts of stuff any given developer might know... but there's a difference between picking stuff up and dryly flash-carding out topics. I [obviously] favour learning what you need by doing than trying to learn a whole book, cover to cover.)