The best way to extend the life of your handpieces is to

call the repairman to service the handpiece every six months.
purchase a warranty for each of the handpieces.
rely on the dentist to perform the maintenance when needed.
properly clean, inspect, sterilize, and lubricate after each use.

properly clean, inspect, sterilize, and lubricate after each use.

Rationale: properly clean, inspect, sterilize, and lubricate after each use – It is the responsibility of the assistant to maintain the equipment in the office, with the exception of repairing it. Most equipment, if maintained properly, can last years without being repaired.