When you are out to eat at a restaurant that has free refills on your drink. If your server keeps your glass full, the server has a high fill-ratio. If the server ignores you and leaves you thirsty, the server has a low fill-ratio.

A takeoff of “kill-ratio”
Our waiter’s fill-ratio is pathetic—he hasn’t come by once.
by Rowdy Librarian January 28, 2020
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