on some of the shoots i'm on we're a really tight crew and we take every chance we can to say things like, waiting for camera, waiting for director, waiting for client, etc… no way it can be done on every job but with certain clients they enjoy as it keeps a light hearted and upbeat spirit to everyone on set. and as long as we're doing kick ass work, thats all that matters.
For me there's also a difference between "doing sound for a student or no-budget" project and a "budget" project.
On a budget project I would rather take care of the batteries more often and use new batteries. On a no-budget I rather would say "it's ok" when there are only 2 of the 3 batterybars visable.
But as I said before, I do try to get the most out of batteries. And when it's a one take/one chance thing, I change them also of course...
Also batteries aren't always to be trusted.... In some cases I can do a hole day with a battery and other times they're already empty after one hour... Which is because of charging half empty....