I've been reading a few posts recently about the Selenium cells in Western meters and Selenium meters in general ageing over time and loosing their accuracy, in an idle moment I just tested my Weston Euro-master that I bought new in 1975 with a Kodak Grey Card against three modern good quality digital meters of known accuracy and it's still spot on to within a fraction of a stop, so although I don't doubt that some Selenium cell meters have this problem it's not so in all cases.