They may be "recommended" every 6 months, but practically nobody does that. In fact, in surveys, only about half of respondents see a dentist once a year. There's also little evidence to support the necessity of twice-annual dental checkups.

Cavities are caused primarily by too much sugar combined with inadequate home care. There is also a genetic component - some people are going to get more cavities than others no matter what they do. Cleanings and checkups don’t really prevent cavities, they screen for them.

The country i come from with free healthcare doesnt even suggest cleanings after reachign adulthood. You get a few free ones once every 5 years. Thats not a major part of healthcare lol