I haven't used it much but it worked well on three holes I needed to enlarge on a car frame. Basically this is the job I bought it for and it did a great job. One thing you appreciate about it is its accessibility. Have you ever tried drilling through the underside of the frame of a car that is lying on its back under the car on car ramps with a drill bit with a 1/2" bit? It's almost impossible to drill the bit with it because of its length It's difficult to position vertically with a conventional drill but the compactness of a step drill makes the job a lot easier.I don't know how long the drill will last but since I've been able to drill the holes I need I think it's already paid off.