I have found, what goes around, comes around.
I am, what I call, a "land use consultant" I am licensed as a land surveyor, wetland scientist, and a septic system designer, everyone needs my services at one time or another. Loyalty to my local multibrand motorsports dealer, has got me universal 15% discount, 30day terms, and more money flowing my way, for jobs, for the owner, employees, and word of mouth.
same goes for the independent shop where I take my Silverado. oh, and I needed a battery for it last week, $90 @ NAPA for their best 84 month battery, I've done work for them too, and I get word of mouth there too.