Preventive maintenance, as the name suggests is: when an object (hardware or software) has been working normally for a long time, at this time on the maintenance of which is called preventive maintenance (usually also known as "maintenance"), expect to avoid failure, continue to play its proper function.
This is specific to a particular facility.
When it comes to the "maintenance system where multiple maintenance methods coexist," this topic is much larger than just the use phase, and extends all the way back to the installation, procurement, and selection phases, and all the way to the design phase, which is the whole process of management from conceptualization of the design until the end of the life cycle.
For example: when designing, it is necessary to give full consideration to the use and maintenance, in the provision of products to the outside world, we must issue maintenance manuals, wearing parts list, to inform the operating skills should be provided, if necessary, to provide training, and so on.
In the selection and procurement, in addition to the above information to the supplier, but also to fully consider their own use and maintenance capabilities.
In the process of use, the restorative maintenance and preventive maintenance at the same time, focusing on preventive maintenance, to give full play to its proper function and extend the service life.
There are many technical details during this period.