Originally Posted by dabvu2498
I've always heard the 1/3 rule, RL. That is, if you're going to cut more than 1/3 of the length of the blade of grass, you should bag it. A couple times when I've had to "make up" some cuts, I'll cut it down to 4 inches, give it a couple days to recover, then drop the blades.
Like SD said, mowing more often at a higher cut is generally better for the health of the yard.
When I'm on vacation, I pay someone to do it so it doesn't get out of hand and it's worth the money to not have to come home and cut the grass the first day back. I keep mine pretty tall anyway and if it goes more than 5 days, it gets crazy.
Good point about the mowing height, in general. Bluegrass, for instance is normally a two foot plant. While it doesn't mind being significantly shorter, the length does make a difference to the root zone, which needs a little protection. And, this from the lawnservice point of view- it's not the height of the turf, but whether it's even and neatly trimmed that makes homeowners happy.