I have 2 lee perfect powder measures that I love. I can't do the math to set them as lee suggests so I adjust them with my scale.
Often times I'll leave one set for a powder charge and use the other whenever I pause during a batch. I rubber band a slip of paper to the measure with the charge and powder written on it. When I go to use it again I check it with my scale to verify it's still on, and it always is.
I normally check the measure at every 50. It's never off. With the way it adjusts I don't see how it could go out of adjustment. I'd be comfortable with just a preliminary check even on a run of hundreds. So, how often should I check for safety?
The Lyman manual suggest checking every 10th charge? Does other measures go out of adjustment easier than the lee ppm?
If I had a lee measure dedicated to a charge I'd guess it would never go out of adjustment.
Bazoo