Many ozone generators have a very short lifespan. Always check the details of the warranty that a manufacturer provides. Ozone can be corrosive and all ozone producing elements build up a film on the plates that dramatically reduces output. Even plates protected by a filter will build up a microscopic film on the plates over time that causes the ozone production to drop. Beware of ozone plates that cannot be removed and cleaned by the end user.
This is especially true of mica plates because the material cannot be cleaned and alignment is very important. So the mica plates have to be permanently built into a handmade assembly for protection. Thus, the mica assembly can become the most expensive component, by far, in the entire unit. Once the inevitable microscopic film builds up on the mica plates or corrosion occurs, ozone output drops dramatically, making it a throwaway product or requiring a costly return to the factory. The most expensive part in the unit will need regular maintenance but cannot be serviced, so the warranty can become somewhat meaningless.