Why do you need to inspect equipment before providing repair cost estimates?

Because every piece and every fault is different and there are many factors that affect repair cost estimates.

I like to know exactly what I am dealing with and that allows me to give you a reliable estimate. There are many reasons something might exhibit a certain set of symptoms. Think of it this way: can you tell me why my car wouldn’t start this morning and what it will cost to fix without looking at it..?