I only weigh every change when I'm loading ammo for extreme accuracy. Not only do I weigh the charge I weigh the brass, bullets and trim as necessary. Everyday shooting loads I load 5 to 10 rounds and fire them. If good to go I run about 50 through and check everything again. Exceptions are my C&H progressive presses. They have a powder bushing and they are preset. Not much you can do but pop out a live round on every pull of the lever.
USAF Retired, CATM, SC CWP, NH NR CWP, NRA Benefactor
To preserve liberty, it is essential that the whole body of people always possess arms, and be taught alike, especially when young, how to use them... -- Richard Henry Lee, 1787