Before having any work performed, ask which cost method the shop uses. Even though you bring in your car with a specific problem, additional repairs may be recommended. If you are uncertain whether the work needs to be done, you may want to consult your owner's manual or get a second opinion. On expensive or complicated repairs, or if you have questions about suggested repair work, get a second opinion or estimate. Ask if there will be a diagnostic charge if you decide to have the work performed elsewhere.
Many repair shops charge for diagnostic time.
Shops that do only diagnostic work and do not sell parts or repairs may be able to give you an objective opinion about which repairs are necessary.