Yeah, it really doesn't cost that much - maybe $10 - over the cost of the oil and filter.
And then you have receipts showing that the oil was changed.
Except you don't know if they actually did it right or not. Or if they screwed the drain plug back in right or crossthreaded and stripped it...same for the filter...the small amount I save by doing my own oil changes is used to buy a good quality oil filter instead.
I don't trust anyone but myself or my father to do something as simple as an oil change. Cause I know we will do it right, but others don't care as much about stuff that they don't own. The ONLY procedure we let someone else do is to change the tires, because we don't have a machine (yet), and even then I am in the bay, watching the mechanics like a hawk.