Once I think the moment is right, I'll often press the button a couple of times in case of random effects (I'm a statistician, after all).
However I rarely bring back more than 50 images, and I delete mercilessly. I would typically keep from 0 to 10. The rest, I delete from the machine: I just don't want to hang on to mediocre images, so I'm a bit amused by people who want to stack up TB's of external HDD's archiving everything they ever clicked at. Maybe one day I'll regret it, who knows? It's what works for me now.