If you never learn you never get better. Even in a very fast paced company, developers should be given a week or two between projects to learn something new (if you feel your developers will slack off, make them tell you what they want to learn then give a brief (5-10 min) speech about it when he's done). It will improve your companies code standard and make you more money in the long run.
Part of your job should be to learn - Karl Seguin - CodeBetter.Com - Stuff you need to Code Better!
