Generally, one should always read the instructions for proper use of vacuum pumps. While today's designs are fairly rugged, these devices will not stand up to abuse.
Oil in the pump is most critical. Running the single stage vacuum pump without oil or with low oil levels is a killer. Not only will the pump not pull the vacuum but the pump will eventually require expensive repair. Leaking oil seals should be replaced as soon as possible. This is a relatively inexpensive repair.
Regular oil changes are necessary for all vacuum pump. Oil changes depend on the amount of use. The more hours of duty, the more frequent it is necessary. Also, a harsh environment may contribute increased stress. In time, the oil accumulates debris from:
Natural wear of the moving components - friction,
Particles suspended in the vapour that is being moved - dust, microscopic particles, etc.
Foreign contaminants that evaporate in rarified vapour - organic acids, chemicals.
This debris forms a heavy sludge that rapidly degrades the function of the pump. Contaminants can break down the seals, cause worn bearings and shafts and corrode reed valves.