I managed to get about 2-3 years' worth out of a DJSN panel pot, across multiple cars. No need to chuck it on, once a panel is protected then it's protected: By adding extra layers you either just waste it (if the wax hasn't cured properly) or you just delay putting the next lot on when you do a proper wash by a bit. Done correctly, a single layer of LSP should be more than enough.
Yes, I've tried layering waxes before over the course of a week, but in all honesty it didn't give me noticeable extra results. Each to their own though, that's the beauty of things like this