Re: Crown/Level, worth it to learn?
It's worth it to learn, because you can buy a slightly used guitar on ebay and make it good as new for just the cost of materials and time. That, and learning how to do mild ding repair.
Check this video out, for the sake of buying, selling or having some peace of mind that if you ding your guitar, you have some recourse.
If you follow the steps carefully, it's pretty hard to mess it up.
There are some things to watch out for still. I masked the fret board off per the instructions, but I would occasionally come down against the tape with the file as I was going back and forth, using a triangular file with the edges ground down. I thought the tape was taking the impact, but after I removed the tape there were pressure marks in the wood. It mostly went away after I went over it with lemon oil, but after that I used two layers or more of masking tape over the frets to protect the fret board better.
Another close call was not the first, but the second or third time I did a level and crown, I was going off of memory thinking I could, and I almost forgot to make the neck perfectly flat before running the sanding block over the frets. Visually, there's hardly an indicator to tell you if you've forgot to do this step, so, that's more of a warning for the second time around.
I definitely think people should do their first level and crown with a guitar / neck they wouldn't be sad to ruin. Sometimes instructions are 100% thorough so you have to fill in the blanks on your own, and that's where things can go wrong, IMO.