This will be controversial. For those who have had one and detected cancer early, they will probably swear by having one. But is it always a good idea for everyone over a certain age? 

When I turned 50 my then doctor (since retired) recomended one and I had one. No problems with the procedure and nothing found. But my new doctor, a younger guy that tends to stay up on research, is not so big on them as a general screening device. If symptoms exhibit, then yes definitely. If family history of problems probably a good idea. He ask my wife and I if we had had one. Then we ask him his opinion on having one (wife is dead set against it and I'm not having another one unless I develop symptoms). He says he has some patients that definitely want one and he never discourages it if a person does want one. But as a general rule he does not recommend a generally healthy person with no family history or symptoms that warrant it to have one. He said bowel perforations are not common, but if you happen to be the one it happens to, it can be a very bad deal. So as a general prescription for a person of a certain age he does not automatically recommend getting one. Only if there appears to be a need for one.

With that background information about my doctor and his recommendations, I present this video which covers a recent scientific study on the subject.

https://www.youtube.com/watch?v=odTIEQbbisw