How often do I need my teeth cleaned? General recommendations for most healthy adults and children are every 6 months. But the actual answer is more complex. The answer comes down to 3 main things; Home care, Diet and Genetics.
Recommended home care for almost everyone is brush and floss twice daily and making sure that you get at least some fluoride (can be from toothpaste, water or mouth rinse).
Diet refers to the types of food you eat. Certain foods are more prone to causing cavities and gum disease. Sugary and acidic foods and drinks are more detrimental to your oral health. Think Soda, coffee, candies and sweets. The bacteria in your mouth use sugars and turn them into acids which cause decay. Also the bacteria form plaque (aka tartar). That plaque contains bacteria and other harmful components that cause inflammation in your gums. That inflammation in your gums is what leads to gum disease (gingivitis and periodontal disease). This plaque is not easily removed with brushing and flossing, especially when it forms under your gums! So when your hygienist cleans your teeth, she is removing that heavy plaque from your teeth and gums (even if you cant see it, its there).
Now, the real answer to this questions has to do mostly with genetics (and bacteria). Everyone has different bacteria and different immune systems. For some, the plaque and inflammatory response wont develop for months. In others, that plaque can start developing in as little as 2 weeks, thus causing a faster inflammatory response, leading to rapid gum disease progression. And again, this is not always about how much you brush and floss or how old you are. I have seen young healthy patients that brush and floss diligently, but their immune system is hyper sensitive to the bacteria and plaque. They develop gum disease much faster if their teeth are not cleaned frequently (every 3 months).
So everyone, even children should discuss this with their dentist and hygienist and come up with a custom plan. Don't just go every 6 months because that's what your insurance covers. And if you don't have insurance don't wait to get a cleaning. Gum disease can cause bone loss and eventually lead to tooth loss. That bone you lose around your teeth will never return. You could be causing irreversible damage to your health by skipping just one dental cleaning!