Likely nothing new here for anyone. But this is the best advice I can think of. It seems to be the stuff that is missing when lists have the kinds of trouble you describe. If you've ever seen a list where one of them is missing, you know why they need repeated sometimes. Don't expect to be perfect, and your members won't expect you to.
Lists are much easier to deal with when the members are willing to forgive goofs.
We are trying to 'hash out' a set of guidelines, in order to prevent such problems as flaming, etc. The list owner is inclined to refuse to accept any more subscribers who use free e-mailers such as Juno and Yahoo, because their advertisements clutter up her nice, neat digest version. My opinion is that, if she really is that perfectionistic, that rather than refusing subscribers, she simply find an individual on the list who is willing to clean the posts up before they go into the digest. Our list has moved several times. The first server we were on was located in Mexico and the software we used did NOT offer a Digest version.