I had used Linux less than a year when I built LFS on a Mandrake 7.x version. I spent about a month reading and re-reading through the documentation and downloading all the source on dial up.
I spent a couple weeks fighting with the fact all the development libraries I needed were not installed.
I went to the LFS newsgroup and searched Google when I had problems. I frequently realized I was way over my head to really understand some things.
I got the basic system built and it worked. It gave me a better understanding of the work that goes into a Linux distribution and I really don't mind if someone else does a good job of it and presents a distribution for my use.
I had a knowledge of basic *nix commands, understood that commands are programs (if you ain't got it, you ain't got it), knew how to consult man pages (won't claim to always understand them completely), check appropriate help groups, and Google. I actually consulted the man pages for every command needed for LFS to try to understand what I was doing.
I have always been glad I did it.
Great comments from everyone so far.