I brought my car in for one repair. I appreciate that they look beyond the repair and identify other items that need attention, thus saving money on future repairs. Their rates are reasonable. And I know they are honest. I had one A/C repair. The dealer estimated about $1000. National gave me a $500 estimate. When I picked up the car, the bill was about $250. The actual problem did not require as much work as anticipated. They could have charged $500 and I likely would not have known the difference. Because I can trust them, they get my major repair business.