I always tip for my vehicle services. I always tip for large deliveries at my home. I hate this newer trend of asking for tips at counter service places. Its like the mob shaking down bar owners, not that I would know much about that.
I am not looking for anything for free, just more attentiveness to the details. I had a friend who would go to a certain restaurant 2x a week and because he tipped the waiter 20%, he would get free bottles of beer for him and his wife. I asked him, as he was devoutly christian, if he thought it proper to steal from the business owner, as all those types do, he claimed I am not stealing.
I was recently stuck at FL for a week, I tipped and I bought donuts. The issue was difficult to diagnose and the tech told me, all of them wanted to figure it out as they did not want to disappoint me and they did not. I see it that just because an hourly labor fee is, say, $200, the tech is not getting that.