How can I create a persistant variable in my integration?

I want to track hours of usage on a 3d printer that doesn’t track it itself. I don’t want to be reliant on another integration like variables for this since that extra dependency makes it harder for folk. There doesn’t seem to be anything native to home assistant to allow an integration to do this - only some ways end users can create their own (semi-?) persistent template sensors.

One idea I had was to store the data (just a single integer) on the ConfigEntry for the device. It seems like that should work although I don’t know what the impact of regularly changing that will have on home assistant.

Are there other ways?

A bonus is if end users can add hours to the value for the estimated hours of use prior to starting to run my integration although I can add that via the config flow if necessary.