Re: What to look for when buying used?
Before buying any guitar, I do a whole step bend on every note on the neck, making sure a tall fret doesn't cause fret-out anywhere. You'd be surprised how many necks appear straight, but there's one fret that causes buzz or fret-out. I find it the most on cheap acoustics.
It's also not a bad idea to open the truss rod cover and give it a little turn left and right to make sure the truss rod isn't siezed. I've bought two used guitars where I brought them home and found out I couldn't adjust the neck. That's a real p1sser because if you sell it, you're screwing the next buyer too.