Prehn's Tacticts book is good reading, though I'm still waiting to use 90% of what I've read in there. Still, a good read.

In crits I definitely try to stay in the top 20 pretty much the whole time - but not up front - as in the 4/5's there will be crashes, and I don't want to get caught behind one. Can't tell you how many horrible crashes I've heard in my short race career so far. Only seen a few. Also the accordion effect isn't as bad in the front half of a race.

And in a RR I don't want to be in the back half of the pack if it splits in two for whatever reason.