I’m 50 and have been using the same dentist practice since I was a child, and through grandfather rights (I suppose) am still NHS, so six monthly check-ups are incredibly reasonable, although I think I’m lucky that I’ve never had anything needed done to my teeth, I didn’t even need a brace as a child as my teeth grew straight. Apparently, so the dentist tells me, it’s unusual to get to my age and never having needed a filling (although that said, I’ve always been obsessive about cleaning my teeth).