Do You Work On Your Own Guitar?

While writing a separate post I got to wondering how many of you guys/gals work on your own guitars. What's the most difficult thing you've done and at what point would you take your guitar into a shop for professional help?

Personally, I've built a Tele from purchasing separate parts. I've done 3 fret leveling jobs and now those actions are pretty low.

I think I would try to tackle everything on a guitar except paint.

I know some people that don't even want to change their own strings. That's perfectly fine, not everyone wants or likes to tinker with things.

I haven't tried building, let alone assembling, a guitar, but along with building an amplifier, it's on my bucket-list. I already have a good idea of what kind of guitar it should be and all the specs are sorted out. I just don't have the budget, knowledge or tools.

I have, however, modified my Les Paul a bit...