> Serious complications occur roughly 0.3% of the time.

https://www.cancer.org/cancer/types/colon-rectal-cancer/abou..., “the lifetime risk of developing colorectal cancer is about 1 in 24 for men and 1 in 26 for women.”

So, it’s a 4% lifetime risk versus a 0.3% per colonoscopy risk. The outcomes for the two risks also are different, but I would think that for many healthy people (e.g. those under 40 years old), the risk of doing such a check are greater than that of not taking it.

Reading https://en.wikipedia.org/wiki/Colorectal_cancer#Screening, that’s one of the reasons frequent colonoscopies aren’t advised.