We moved to Phoenix recently and were looking for a mechanic. I brought my primary car to the shop the first time.
My wife then brought her car into the shop with an indicator light on for the tire pressure. The shop found the problem, explained it, and fixed it without charging her anything. Even though I had brought my primary car in once already, we did not tell them that we had a second car in the family yet. That the shop was willing to do a simple fix even before knowing that we were actually repeat customers says a lot.
(For the autophiles, we moved our car from Seattle to Phoenix. The temperature difference caused the pressure setting to be triggered.)