My bike shop has been very good to me over the years. I've bought 5 bikes in 10 years (since sold 3 of them). They have never hesitated to make a tweak or adjustment, even truing a wheel on the spot, and mostly without any charge.

I give them tins of homemade Christmas cookies (several varieties) at Christmas, and once or twice again at some other time during the year - usually after they did me a big favor. They save the tins to return to me so I will fill them up again. LOL!