I've upgraded my kernel on my home's PC last night. I didn't recompile it ; I upgraded via RPMs. That's the first time I do that, and (half-suprisingly) I didn't run into problems. I have a RedHat 7.0 box, and used the kernel RPMs (and their dependencies) from 7.1. After the upgrade I had to modify /etc/lilo.conf and re-run lilo(8), and insert some tweaks in /etc/modules.conf. Everything appears to work (although I haven't tested the p4 client yet).
Why am I doing that ? To support my brand new DSL modem !