Let's take a wedding for instance. You can't go back and re-shoot a wedding, which is why you carry several cameras and overshoot with all of them. You'd be crazy not to overshoot with those cameras, because. . . you can't go back and fill in the gaps later on. To some extent the same thing's true of any commercial shoot. You may be able to go back and re-shoot but doing that usually is a seriously expensive operation, and if you blew it and didn't end up with the coverage the job called for it may be somebody else who gets to go back and do the re-shoot while you lick your wounds. (All of which is why I hated doing weddings and quit doing them not long after I started doing them, and almost lost a pro friend later on when I flat refused to fill in for him on a commercial shoot when he'd taken on one shoot too many.)
Which is not to say that the excess stuff if bad. It's just repetitive.
But then, there was Brassaï and the story of the kneeling tripod when he came to shoot his friend, Lawrence Durrell. He made only a couple shots, and as he told Durrell: "Yes, I only take one or two or three pictures of a subject. I find it concentrates one to shoot less. Of course it's chancy; when you shoot a lot you stand a better chance, but then you are subjecting yourself to the law of accident - if accident has a law. I prefer to try and if necessary fail. When I succeed, however, I am much happier than I would be if I shot a million pictures on the off-chance. I feel that I have really made it myself, that picture, not won it in a lottery." (From an October, 1968 MOMA press release.)
Now that's my kind of photographer.