I consider myself a person who does their own repairs. I buy the factory service manuals for my vehicles. Having the factory diagnostic procedures is very helpful even if you decide not to do the work yourself -- it's helpful to know what repairs need to be taken to solve a particular problem.
Car repair can be a fun hobby, but in my opinion it's rarely cost effective. Most procedures require single purpose tools. I elect to do my own work because I'm particular about the quality of the work and I enjoy doing it.
I look at it this way--I can usually get new OEM parts at less than what a shop would charge me for reman or knock-off parts, and any tools that I need end up costing less than the labor at shop rates. I end up spending less than I would at a shop, have the tools for next time, and I know the work was done right, on my schedule.
Oh, many auto parts stores will rent or loan (for free!) tools that you may only need once. Around here, you can even borrow the OBDII code scanners for free.
My grandad runs a local auto shop, and I would have been hard-pressed to not learn how to repair my car. I did all kinds of work on my '83 Ford Ranger, and a good amount of work on my '90 Daytona, but I've gotta say that I'm a bit afraid to mess with my '07 Impreza. With all the computer control systems and other sophisticated components, I just don't feel like I should be messing with it. On top of my fear, I also lack the necessary (and expensive) equipment that's needed to e.g. clear the check engine light.
I do nostalgically miss tearing my old Ranger apart, and tuning the carburetor, and generally understanding exactly how it worked. But then again, my Impreza just doesn't need to be tuned -- it just works.
I used to have Volkswagon rabbits and even replace the disk brakes and ball joints. for the ball joints, I had to buy a "pickle fork" and drill through the rivets. It was intimidating at first, but I figured it out and even did an "eyeball" alignment using sticks as guides. My mechanic skill reached a peak when I had an accident and had to rebuild the front end and the rack-in-pinion steering from an almost matching parts car. But I was a student and had more time than money. Now, like plumbing, I'll pay someone else to do it. I'd rather be doing something else.
But I also got lucky. My mechanic is a second generation mechanic who went back to the family trade after getting a masters in mathematics.
In this case I will honestly say I certainly wouldn't trust myself beyond changing the oil or tire or something. I would imagine I could learn to do enough car repair to get by and it is interesting but up to this point I have spent most of my time trying to get better at other things and haven't put any time or effort into learning to repair my car.
I _can_ repair anything on a car but I'd rather not. I'm very fussy and am only happy when my work area is nearly surgically clean (dust and dirt are the enemies in car repair). Watching others work on my car can be maddening, as I watch them make one mistake after another. Consequently I choose my mechanics carefully and don't watch them anymore!
Car repair can be a fun hobby, but in my opinion it's rarely cost effective. Most procedures require single purpose tools. I elect to do my own work because I'm particular about the quality of the work and I enjoy doing it.