How often do you folks realign the belts in your treadmills. I have a Life Fitness T3i and I find that running between 13-15 miles a week that the belt has drifted by 2 cm to one side of the roller or other (sometimes more but i think thats in relation to how much incline I use). Its simple enough to fix but I'm wondering if I need to increase the tension on the rollers to keep the belt from drifting around as much.

How often do folks who work in gyms adjust the belts or how about home users? This is not important enough for me to have a $75 service call over, I'm just wondering if the belt has stretched out from use, equally important I dont want to put too much strain on the drive motor.