I called in a mountain lion with it once... Don't think I ever had a deer respond to it, but I don't call all that much either, except during the rut.

Pre rut I hardly use it, usually I'll use it when I'm running out of steam and about to get down out of the tree. I'll flip it, and give it another 20 minutes or so to see if anything comes in.

During the rut I'll flip it about once or twice everyhour or so.
Post rut I usually just stay quiet.