Maintenance is usually easy to give an estimate that is very close. Things that change the total is the condition of fluids and filters and do they NEED service. In most cases my estimate for service will include all items so will be a high end estimate and could come in lower if fluids and filters are still in good shape.
I will give you an estimate for service and/or repairs by phone or email for the cars and trucks that I service. I will need the Vehicle Identification Number for the vehicle which the estimate is for. In some cases I will need to call you back because I will need to check part prices. In some cases a estimate is only possible after inspecting the vehicle. When calling around for estimates beware of an estimate that is much lower than all others, it could be a low ball to get your car in. More important than price, is the person you are talking to knowledgeable about the problem you are having ?
Electrical Problems are the 'Black Hole' of giving a estimate that will be close. Most electrical problems are 90% finding and 10% fixing.
ENGINE & COOLING SYSTEM REPAIRS
Estimates for engine and cooling system repairs are not that hard to come close if the problem is known. Headgasket problems would be the exception as it is hard to estimate the damage until the head(s) are off.
CLUTCH / TRANSMISSION REPAIRS
Clutch / transmission repairs are much like engine repairs to get a realestic estimate.
Brake repairs can be broken down into three areas, front brakes, rear brakes, and fluid system. Inspection is the only way to get a right-on estimate, but in most cases I can come close.