Depends if fixing it will bring a good chance that it will be good for a long while yet...and depends on whether the car's likely to become a classic, worth preserving for that reason... lots of other considerations...like... if you decided to ditch the car and bought a new second hand car.... you may end up with a car that's even worse... no guarantees really with a second hand car.
Yes. if you've had a car since it was new and now the BB is very low, but you know the car is dependable and you love it, and have babied it and kept it tip top, consider keeping up the repairs. I just sold my mother's car which is an 02 and had 24,000 miles on it. The BB was nothing but the guy who bought it knew he was getting a steal and I got more than twice the book price for it.
I find new cars become junk when out of manafactures garerentees ...with so many electrical components faults become often uneconomic to find and repair....
I have a friend with a big BMW ....it had problems with its door locks and after spending £5,000 plus, even BMW couldn't find out what was wrong with it....The car was no more then four years old and they just got rid of it after....
Old vehicles are far easier and cheaper to keep running or fix if you ever break down.....
Depends on the car. I have an old Merc as a toy. It's not worth an awful lot, but the money that's been spent on it so far is around triple its value. I'm not expecting to ever get that money back, but then again, I don't intend on selling it.
What you must understand is that, in most cases, you'll never get your money back on a car that you purchased, regardless of whether or not you spent money on it. Even buying new is to me, a bad idea. The minute you drive it off the showroom floor, the car has lost a few thou there and then.
So. If the car is decent to begin with, and not infamous for defects and breakdowns, it probably is worth spending money on. Especially if the will give you years of trouble free service.