In general, vacuum cleaners need to have their bags changed or their dirt containers emptied. Some vacuum cleaners may have belts that will need to be inspected and changed. Most bagless and some bagged vacuum cleaners now have filters that may need to be replaced or cleaned every month or few months.
In addition vacuum cleaner cords need to be examined at least seasonally to make sure no fraying wires are evident. The roller or beater bar of the vacuum cleaner will also need to have hair and fibers cleaned from its surface.
Your vacuum cleaner dealer should have suggestions to go along with the user manual about a maintenance schedule that will keep your vacuum cleaner in the best shape possible.