How common is an incomplete colonoscopy due to a tight splenic flexure bend?

If the colonoscopy prep was adequate, ask the GI physician about a repeat attempt, depending on the reason for the colonoscopy, since your age (25) is early for routine screening. A repeat may be appropriate if the reasons for the procedure are secondary to a positive fecal blood test or GI bleeding.

In the hands of a skilled endoscopist it should be rare. Not sure the reason for the procedure in such a young person, but if evaluation of the colon was important enough to do a scope you need a repeat exam or at minimum, a double contrast barium enema to evaluate the ‘tightness’ and the remainder of your colon. See a skilled colorectal surgeon or gastroenterologist.