I would add not to leave them with the shutters cocked, especially if they have cloth shutters. Over time this will stretch the springs and throw the shutter speeds out of adjustment.

I just try to use a different body with each roll of film. This doesn't always work - there are some films which I can only use in two or three cameras, either because the rest don't have a high enough ISO setting or because the metering is less accurate on some than others.