The life span of all types of diamond drill bits is affected by the hardness and abrasiveness of the material being drilled, the thickness of the material, plus the speed of the power drill, the amount of pressure used and the use of adequate lubrication. The hardness and abrasiveness of materials can vary significantly. Even materials which appear similar have varying degrees of hardness and abrasiveness. Each individual's drill speed, pressure and amount of lubrication also varies significantly. As a result it is nearly impossible to estimate the life of a diamond bit.
For example: On standard 1/8" glass, an electroplated diamond bit may last for 200 to 300 holes, or more, depending upon the specific glass and specific drilling techniques used. Drilling in 1/4" glass, being twice as thick, will normally produce only half as many holes over a drill bit's life, if the glass hardness and drilling techniques are the same.
Lubrication has a significant affect upon drill bit life. Using a good water lubrication method can double or triple drill bit life. The effectiveness of various lubrication methods are discussed in the lubrication techniques section.
On the extremely hard and abrasive materials, such as granite or the newer "super-hard" porcelain floor tiles, a diamond bit may only produce 8 to 15 holes in 3/8" material. However, the same bit may produce as many as 20 or more holes, all depending upon the specific material, the thickness and the specific drilling techniques used. Tests on some of the less hard, class III floor tiles have ranged from 40 to 60 holes. Porcelain wall tile can have bit lives of from 8 to 60 holes or more, depending upon the exact material while ceramic wall tile can easily result in hundreds of holes depending upon the hardness.
These examples are are all based upon extensive testing in different materials using proper drill speeds, drill head pressure, and lubrication. Test results were much less, using poor drilling techniques, and extreme tests using improper drilling techniques often resulted in a bit "burning up" after only one or two holes.