I can't even begin to guess at how many hours I have accumulated over the past 27 years of ownership.
From the first brake job to a couple of motors. Engine bay paint, fitting headers, adding rear sway bar, putting interior and painting undercarpet, swapping guages, on and on and on.
I don't work on other peoples cars, if I do it's for free. A Jeep club I belong to recently met and swapped a good body onto the frame of a jeep that got rolled. That was fun! There were about a dozen of us working on various parts of the car (okay, usually only one or two actually doing something at the same time it seemed). The cool part was the various skill sets that had come together.
Final thought. I do almost all of my own work. Transmissions, rear ends and paint are the only things I don't do. I justify buying tools based on the money I save. I am trying to decide if I should swap the convertible top myself or not...