The answer to the question of when an oil is used up can only be given in the context of the machine, the environment and the maintenance and servicing strategy. At the same time, it is about the “how” of an oil change, whether with or without flushing, system cleaning, etc. It makes no sense to use an oil until it is actually no longer fit for use and destroys the machine, which is many times more expensive, or significantly impairs its service life and reliability. It is also technically and ecologically nonsensical to change an oil far too early and thereby gain a supposed advantage in terms of reliability.
The online training, which consists of 2 modules, takes a pragmatic look at both questions and uses practical examples to show what is important.