I use a weston master V, and have tested it against a sekonic digital meter, and the weston is spot on, it is in use every time I take a photograph as none of my cameras,from the 30's to 50's, have built in metering,I never keep my meter just around my neck, when not in use I keep it in my pocket, that way it is protected from light when not in use, which, according to Newton and Ellis is the best way to keep the cell working for a very long time, Richard