I had bought new tires once and after the "free" tire rotation it took two people standing on a pipe on the end of the lug wrench to get one of the nuts off.
I've found that I can rotate tires or change the oil quicker than I can drive to the quick change places to get it done without having to worry about what they screw up.
People say their time is worth too much to do it themselves but if it takes 15 minutes to drive there, wait 15 to get the work done then another 15 home, thats too much time when I can do the work in about 30 minutes total.