I would never even load a mag to it's full capacity. At least download by two or three rounds.
I also never leave my magazines loaded for any longer than possible. Like when I'm at a match, I unload all of my magazines between stages and only load the magazines I'm going to use when I'm on deck.
If I'm just at the range practicing, I only load two rounds in a magazine at a time, but I only shoot one round. This keeps the tension on the spring at a minimum and prevents follower wear.
As soon as I get done shooting I fully disassemble all of my magazines, clean them with q-tips and store the springs completely relaxed.
"If you're not shootin', you should be loadin'. If you're not loadin', you should be movin', if you're not movin', someone's gonna cut your head off and put it on a stick." -Clint Smith