I've got mine set at 20, 30 & 40.

Like Rob, I can't tell enough of a difference in point of impact from 10 yards to 20. I also don't like shooting at live game past 40. To be honest, I'm not too crazy at it at too much past 30. There's simply too many things beyond my control that can happen; the animal only has to take a step or two at 40 yards at the exact instant you touch your release, and you've gone from a perfect double-lunger down inside of 80 yards to a six-hour to overnight wait for a gutshot animal.

I'll also throw this out there, as someone before told me this was a helpful tidbit:

My 20-yard pin is green (for "You've got the green light; let 'er rip!); my 30-yard pin is yellow (for "let's take our time on this one and focus); and my 40-yarder is red (let's think about this one; are we sure there's not gonna be a better shot?). This is also the reverse order that the lights begin diminishing in brightness; I lose visibility of my red pin first, then my yellow, and -- last of all -- my green pin. When it's getting that dark, I don't need to be shooting at anything past 20 anyway until I finally lose enough light that it's time to pack it in.