Most tech's at the tire places don't like to be told how to do their job or ask if they did it afterward (I asked one time when I did use an oil change service if they got all x grease fittings).
Its soo much better to do it your self. I have seen issues in forums where people have had ball joints seperate (basically your wheel falls off) and posted pictures and ranted about the maker of their vehicle etc. Then you look at their pictures and the inside of the ball joint is dry and rusty when it should have been covered in grease and you ask about it and they tell you that every 3000 miles they took it to x place for maintenance.
We had an minivan years ago which I tool for an alignment and the place said they couldn't align the rear becaue they couldn't get to the bolts due to the ABS ring in the way. Ours was an AWD version and you had to take off the axel nut and push the anelinward to get the bolts loose, and those instructions were listed in a $12 chilton book I bought an an auto parts store. It just goes to show that there are so many differnet brands and models that the shops can't learn everything about them all so you have to do some work yourself.