I did a post a while back for camera operators showing ways that they could help make their Dolly Grip's life easier ( it's here). One of the points I brought up was I have to see it once. I did a show a few years ago where the camera operator would constantly verbally correct the first run-through. As in, "Too slow, too slow." or, "Boom up quicker when he stands, we didn't make it." This nearly drove me insane. Finally, I told him, "It's the first time I've seen it. I know how to do it, I just need to see it once." I think a lot of people don't realize that besides just seeing it, we also have to get the feel of it. We're getting upwards of 800 lbs of dolly, operator, and camera moving and stopping with a person* and often simultaneously booming up or down, and trying to get our timing right as well as hit a mark. Remembering how it feels to do a particular move is often just as important as remembering how it looks. Those first run- throughs are how we learn what is going to be required as far as how much strength to use to get the whole thing going and stopping again. If I'm too slow in one spot on the first rehearsal, that's actually a good thing because it tells me what I have to do to make it work. I can remember how much pull or push I used and tune it up on the next one. The actors always do it differently than the stand-ins. This is one reason that I don't like to do too many rehearsals with stand-ins because the feel of doing it a certain way gets ingrained into your muscle memory and then you have to completely recalibrate it all with the actors. So if the first time with actors is a little off, you don't have to tell me. Believe me, I know when it's off, and where. I'm just figuring out what I need to do to fix it.
* Or whatever we're tracking. In the last six months alone, I've had to keep up with an owl, a falcon, several cars, and fire. (yes, fire).