I like to have a meter assigned to a camera - as in, when I am using camera X, I use meter A; when using camera Y, I use meter B, etc. This does limit the number of cameras one uses or the number of meters needed. The big issue is consistency: if your meter is wrong but consistently wrong, it doesn't matter since you quickly learn to adjust the settings on the meter; if your meter is wrong and not consistent in its' wrongness (as ic-racer mentioned), the meter is useless. At that point, either send the meter for servicing or get a new one.