Had to do it for uni.
Building and compiling is really easy. Kernel programming in Linux, on the other hand, is a nightmare with how bad the documentstion is.
So you "make config" once and then you just tweak it from time to time! I used to run make config until I discovered xconfig (when X was xfree86) and settled on menuconfig.
I was still using menuconfig on Gentoo until around five years ago. OK I still have one or two Larry's lying around doing useful stuff but generally I just copy the old kernel config to the new one and compile away with genkernel.
make config did take a while back in the day. You literally run through the entire kernel's options one by one: y/n/m for drivers. I haven't done that since 2.0.x days. Then you forget to sort out lilo and reach for the boot floppy. No I don't miss those days.
