The thickness, hardness, and abrasiveness of the material being drilled, as well as the speed of the power drill, the amount of pressure applied, and the usage of sufficient lubrication, all affect the life span of all types of diamond drill bits. Materials can vary greatly in terms of their hardness and abrasiveness. Even seemingly comparable materials can differ in hardness and abrasiveness. Drill pressure, speed, and lubricant levels differ greatly between people. As a result, it is extremely difficult to predict how long a diamond bit will last. Click here for overall Bit.
An electroplated diamond bit, for example, may last for 200 to 300 holes on standard 1/8" glass, or more, depending on the glass and drilling techniques used. Drilling in 1/4" glass, which is twice as thick, will typically produce half as many holes over the life of a drill bit if the glass hardness and drilling techniques are the same.
Using a good water lubrication method can double or triple drill bit life. The section on lubrication techniques discusses the effectiveness of various lubrication methods.
A diamond bit may only produce 8 to 15 holes in 3/8" material on extremely hard and abrasive materials such as granite or the newer "super-hard" porcelain floor tiles. However, depending on the material, thickness, and drilling techniques used, the same bit can produce as many as 20 or more holes. The number of holes tested on some of the less hard, class III floor tiles ranged from 40 to 60. Depending on the material, porcelain wall tile can have bit lives ranging from 8 to 60 holes or more, whereas ceramic wall tile can easily result in hundreds of holes depending on the hardness.
All of these examples are based on extensive testing in various materials with appropriate drill speeds, drill head pressure, and lubrication. The results of tests using poor drilling techniques were much lower, and extreme tests using poor drilling techniques frequently resulted in a bit of "burning up" after only one or two holes.