Invisalign Final Retainer - Bad for my Teeth to Only Wear It at Night?

When treatment ends, the bone supporting teeth is still fairly soft.  If a retainer is worn 24/7 at first, the bone can get dense and allow the teeth to settle.  At that point night time only wear works.

It's not that it's bad for your teeth, it is the minimum needed. You need full time wear long enough for your teeth to stabilize in their new position. Eventually you should be able to where then just to bed. Trust how they feel. If they feel tight you need more wear. If your teeth feel like they move you need more wear. Your body and your retainer are better telling factors in terms of if you need more wear or if bedtime alone is enough, than a rule of thumb a doctor with tell every patient.

In my office when I complete an invisalign case I usually recommend that my patients where the retainers as often as possible to allow the teeth to settle.  After the first few months night time only wearing is required for as long as you do not want the teeth to move back to where they once were.