Whatever works for you, it's cool. Me, free rotations and balance go with tires purchased at Discount Tire, so ~6k+ mi. get it done (also do free rotations even on tires not purchased at DT).
As noted above, does help with keeping tire warranty valid, in force at DT. And no real hassle, usually ~30 minutes. Also side benefit, gives me a chance to get a good look at brake pads.