While driving an older vehicle has its benefits (most notably no payments...no depreciation, lower personal property taxes, sales taxes, insurance premiums, etc...) There is one major thing that drivers of older cars cannot avoid is repair bills.
Fact: most major repairs can be completely avoided with routine maintenance (oil changes, transmission fluid changes, etc...)
However, there are some parts of a car that maintenance will not prevent from breaking. Hoses and belts need to be replaced...as they wear out. Your thermostat eventually will fail regardless of how faithful you are to winterizing your car. Suspension components eventually wear out and break, the fan motor will one day burn out, your water pump will one day fail etc...
I keep my mechanic honest. I use two of them, and neither one knows who the other is. If both mechanics agree about a repair that needs to be made, I make sure it gets done, and then I get bids from both of them. Don't hesitate to get a second opinion on any work that is suggested or recommended. Also pay attention to recommended service that comes attached with a brand name, such as BG. Some recommended service may really need to be done, which is why you get a second opinion. So far, I've had over $1200 worth of work that has been suggested to be done on my car, by both of them, which hasn't, in fact, needed to be done.
Sometimes, a less expensive fix can solve a problem quicker and easier than an expensive one. The most notable one was one of the two recommended replacing all of my front ball joints for approx. $2000. When I took it to the other mechanic, they took apart the front suspension and found I only needed CV Joints for $500. The CV Joints fixed the problem, the ball joints, while they should be done at some point, would not have solved the issue I was experiencing. Find your limit, and whatever it is, when a repair goes over that limit get a second opinion whenever a repair goes over that amount.