Getting one annually is not recommended for most patients. After my bowel resection, I had annual colonoscopies for five years, then every three years, now every five (the normal recommendation for my age cohort).

Colonoscopies are no big deal from my perspective, but they do have some risk; bowel perforation being the primary one. The prep stuff is the worst aspect for most patients; I used to love lemon lime Gatorade before I used it once as a way of drinking the liquid laxative...