The short story:
A time-based maintenance plan triggers a work order at specified time intervals.
A counter-based maintenance plan triggers a work order as soon as a certain counter value has passed.
A combined maintenance plan triggers a work order either at a specified time-interval or as soon as a certain counter value has passed.
The long story (with example):
EXAMPLE: You have a car and you would like to change the oil and the air filter every 10000 Km or every 6 months.
1. Start by