Well said, woodworm. For me, it really depends on what I'm shooting. For example, if I'm shooting a client for a portrait, I'll usually keep everything that's in focus and well-exposed. That doesn't mean that I'll show them to the client. I'll usually show around 6-10% to the client. Of these, I usually have 1 or 2 that are "the one", although sometimes not,
If I'm shooting wildlife, it's a totally different story. For the most part I'm trying different compositions, exposures, zoom lengths, etc. It's not so much about perfect framing or tack sharp results but more about the "feel" of the piece. Again, I'll shoot maybe 150 shots in a lengthy session and I'll have a dozen or so that I think are worth doing something with. It seems like about a 10% hit rate but for totally different reasons.
Shooting macro work? Now it's down to focus point, depth of field, composition, etc. I'll get more "keepers" with macro but I'm usually a heck of a lot more demanding about what I'm satisfied with.
So, I guess I would summarize to say, the higher the control I have over the shoot, the more "keepers" but the expectations also go up as well. Lower control over the situation, I'll be more satisfied with a "good enough" that might not make it past the second screening in a controlled shoot.
Does anyone else have a similar approach?