Prevention is easier than recovering from neglect
The most useful maintenance is the work that prevents a small issue from becoming a failure or permanent damage.
Dust, early oxidation, a loosening screw, an intermittent cable or a battery left in place too long may look minor. If ignored, they can affect other parts and require more invasive work.
Build a simple routine: observe, clean, verify essential functions and intervene only when you understand the task. Preventive maintenance does not mean frequently dismantling the item; it means noticing changes early.