I have these on all my spice jars. I never shake my spices.
Every time I use a spice I take this thing off, pour or measure out the spice I want, and then put this thing back on.
Last weekend I had about 4 spice jars out and was wrangling all these stupid things and I thought, “Why do I even keep these?”
So I took them off and washed them and put them in a drawer in case I change my mind later although really it’s just going to be something to throw away someday.