I do my own work, and a bunch for a truck company in town.
5 Chevy trucks, one with a mechanical diesel engine, a diesel tractor, a Jeep, some sort of car made in Japan, and a red-haired-stepchild of a Land Rover. Have the factory service manuals for most of them.
I still have and use my tach and dwell and my Sun timing light. Have added a vac gauge, high pressure fuel pressure gauge, multi-meter, and assorted micrometers and such. Thinking of buying a tire machine and an injection pump timing light.
The last time (an it will stay the last time) one of my vehicles was in a service garage, it was to replace a part that was covered by GM's lifetime warranty (had a failure 300 miles from home, so had it fixed at a dealer). This local Chevy dealer said I had to buy $350 in additional parts, else they wouldn't fix it. After some discussion with the franchise owner, they decided they would fix it afterall. I don't need that static, so I do it all now, warranty or not.
The truck I prefer to drive has over 500,000 miles on it, and I have a spare engine and tranny for it if I ever need it. Even have a new in box Quadrajet for it, with the correct manufacture date and tag number for that particular truck.