There are several reasons why it is recommended that you see your dentist every six months for a check-up:

1. Prevention of tooth decay and gum disease: Regular dental check-ups and cleanings can help prevent tooth decay and gum disease by removing plaque and tartar buildup, which can lead to cavities and gum infections.
2. Early detection of oral health issues: Regular check-ups can help detect any oral health issues early on, when they are easier and less expensive to treat. This can include tooth decay, gum disease, and other dental issues.
3. Oral cancer screening: Your dentist will also perform an oral cancer screening during your check-up, which can help detect any signs of oral cancer early on.

Overall, regular dental check-ups every six months can help you maintain good oral health and prevent any potential dental issues from developing or progressing.