We go twice a year (NL). But we also lived in Germany for a while where it was once a year and they wouldn't do the extra polishing/whitening unless you paid a

We go twice a year (NL). But we also lived in Germany for a while where it was once a year and they wouldn't do the extra polishing/whitening unless you paid a lot extra. But I think for a long time you also had to pay extra in Germany to get white composite filling, insurance would only cover amalgam fillings.