I had a bunch of 1/4 inch holes to drill and tap in some mild steel. I had
two battery drills one top of the line Dewalt and one cheapo model. They
both seemed to have the same amount of power but with the cheaper model I
went through bits like crazy. I finally discovered that due to the cheap
bearings in the cheap drill there was vibration in the chuck which
ultimately ate the bits. In this instance the cost of the bits far out
weighed the savings on the cheaper drill.