When I shot my Rollei a lot it was not a problem, film wasn't in long enough for me to forget what it was and the Gossen was always set to the right ISO. Now that I'm older, shooting a Blad with a couple of backs, and film rolls don't come in a box anymore, it is more of a problem. Worse with 4x5, just the other night I ran a couple of sheets of E6 threw some Xtol. I think I need to hire a lovely assistant to help me solve the problem but the wife says its not gonna happen.