There is no norm even to have any scan post treatment or routine scanning after that, and NCCN guidelines says it's only for certain T3, T4 disease only, which should be between 3-6 months post treatment, unless there is suspicion of cancer. It's basically up to the doctor, hospital. The professional otolaryngology association, NCCN, does have recommendations for follow-up exams every 1-3 months the first year, etc. which involves an exam, probably the flex scope at that time. I have not seen any requirement for an endoscope, under anesthesea every month, unless you mean the laryngoscope/flex scope done in the office.

All my doctors do 3 months post PET/CT scan or wait a month or two for more healing, and then a scan 6 months after that, and seems most follow this, but not all do.

Good luck.