Kor whitening maintenance

Hi all. I had kor whitening done recently and finished up about 3 months ago. Since then, I’ve had one veneer on my front tooth placed.

Can anybody speak from anecdotal experience how often one should re whiten with the kor whitening gel (aka maintain). Im a non coffee, non tea and non red wine drinker.

My dentist said to do it “whenever I feel it’s needed” but it’s difficult to gauge with the veneer. I obviously don’t want to re whiten all my other teeth and then the veneer looks darker. I’m also unsure how much more my teeth may whiten after one maintenance night of whitening.

So really I’m just wondering what a typical maintenance routine looks like (every 3 or 6 months for example)