I find that it depends a great deal on the subject and environmental circumstances. For example, in this post (https://photography-on-the.net …/showthread.php?t=1230256), the top shot represents the only shot out of probably 100 attempts over the last 6 months that I deem acceptable of this kind of fly. However, that terrible rate of keepers is based on these facts: (1) that species never stops moving around when they don't just fly away entirely; (2) they tend to land on wispy branches that sway a lot in the wind, but you can't try to secure the branch or the fly instantly flies away; and (3) the dark bodies don't reflect much light, so even when a shot is sharp, at least part of the fly's interesting details are obscured in shadows.
Compare this to a quick shoot I did last night of a very cooperative weevil. The weevil almost wasn't moving at all, and it was on a table, so I could rest the camera and lens on the table. The added stability and control meant that every shot was in focus and had no motion blur. They were all "keepers" in the sense that there was nothing technically wrong with any of them. When I get around to processing them in a couple days, I will ultimately only post the best one, but they are all fine.
So, ultimately, you really need to either (1) do things that ensure a higher keeper rate (e.g., secure the plant on which the subject is sitting, brace your body/camera against something solid like a wall or monopod, hold the plant with the same hand you use to brace the lens, make sure your flash is oriented correctly to get good light, etc.); or (2) be satisfied with a lower keeper rate when the circumstances are difficult. If it's super windy and your subject is a skittish long-legged fly on a wispy branch, 1 out of 20 keepers is a fantastic rate. If it's a slow-moving weevil on the ground, you should be aiming for 1 out of 3 at the worst.