I Rotate and balance all 5 of my tires with every oil change at 3,000 miles.
Yes I know, it might be a little over kill, but hey, it's free and seems to be working out great.
I am currently running Goodyear Wrangler Duratracs 31x10.50R15
I've had them 2 1/2 years and haven't even come close to using 50% of the tread.
This first pic is the rotation pattern I have been using, but I'm wondering if I have been doing this wrong? Maybe the second pic is better