When my car is "in warranty", It goes to the dealer, once a month for a check-up, but that hasn't happened since 1973. Otherwise, I do it myself. Getting harder to move around under the car anymore, so I may have to look for a local shop for oil changes in the next year or two.
Since we don't drive as much, our 96 Cadillac and 98 Lincoln, don't require too much in servicing. Neither one has been to an garage in the past 3 years. Since the book value for each car is about $2000, the few annoyances that come from age... we just live with. The last major fix I did myself... four wheel brake job... new discs, fiber pads, total cost $215.
Both cars have ride level suspension systems that don't work right, so the onboard computer shuts them down. No bother... the default ride is a little bit harder, but with a repair from the dealer the cost is between $4K and 5K.
Also, on the Caddy, the onboard diagnostics light up the check engine warning about once every three months, but that's common with that car (Map sensor triggers after long idle). Just a few button pushes to turn off the light. My guess... The Check Engine light is profit magnet for dealers, especially in states that require emissions checks. The average owner is at the mercy of the dealer.
The other problem that really bothered me, was that the slow automatic trunk pull-down stopped working and I had to disconnect it. $600 to fix... no way. I liked that classy feature.The cars still look great,white with blue convertible tops and no nicks or dents. We'll probably never get another car.
About 5 years ago, I had a very noisy squeak in the steering, and, worried about a steering loss, brought it to the local Lincoln Dealership. Received a call... Cost to repair would be $5,000. No Way!... Used a printer ink syringe and some motor oil to squirt into the rubber boot of the linkage. Total cost... $0. Never problem since that day.
Oh... BTW... when I went to pick up the car after getting the call about the estimate... the damned head mechanic said he wouldn't give me the car back unless I signed a release. I was bigger than him, and at the time pretty strong and uh... aggressive. That little experience cost him, as I posted the scam on our community bulletin board. 350 car owners out of the Lincoln dealership loop in our town. Older folk are at risk for these guys.
And so... dealer trust?... No!
Both cars have excellent mechanic websites that cover every imaginable problem. If I were to ever give advice on car repair, I'd suggest finding the very best mechanic website in advance. My experience is that whenever I sense a problem, a visit to the website either gives a simple fix, or at the very least, will suggest a reasonable cost for any repair at a shop. I don't trust the dealerships.
Here's the best site for Cadillacs as a example. It's a huge site with 130 thousand members, and user friendly.
You may have to dig a little to find one of these specialty sites for your car make, but it will be worth the trouble.
http://www.cadillacforums.com/
+1 on the busy local mechanic/shop.