About 10 years ago I bought a electronic digital scale to use for handloading. After a while, I noticed my handloads were performing irrationally. One day they would be clocking velocities higher or lower than expected, or showing pressure signs with established loads. I about went crazy looking for the culprit. Then I determined the electronic scale wasn't holding calibration during my reloading sessions. I threw the wretched thing away and went back to my trusty RCBS balance beam scale.
This episode prompted me to purchase a set of check weights to use with the balance beam scale just to make sure it doesn't go bad. Of course it never has and having the check weights readily available changed my reloading procedure. These days, I set/calibrate the scale to the charge I intend to load with the check weights at the start of every session. This way I'm certain the measured charge weights are correct every time. It only takes a few seconds to do this easy calibration, plus it serves as a nice confirmation the scale is set properly. So for me, purchasing a set of check weights was a very good thing.
BTW, electronic digital scales these days probably hold calibration well. But I'm not interested in finding out.
