Forgive me to think that I might be defending a dealer but...
Consider the care of your (especially) out of warrenty car as you would your body and your health.
The doctor and the mechanic can give you insites into your health and your cars health but in both cases your the owner.
You would never hold your doctor responsible for your health with the differences of life style and genetics we have. We trust them to make their best guess and act accordingly. No guarntees only the trust we get their best work.
Unfortunitly your relationship with your mechanic is similiar. They're only guessing, abet with some substantial education and experience
I may offer two axions:
1. Randy's rule of repair-- Fix the easiest cheapest thing first, as cheap things tend to break.
2. The Great Commandments
Love what He has created
Take care of yourself
Take care of what's important to you (people and things)