I used to use refillable K-cups at work. The guy I work for uses Keurigs and there’s a perfectly good second cup of coffee in one of those that he doesn’t want. Just shake it around, tap it to redistribute grounds.
And, he’s switched to my favorite variety.
Cheap win.
I love the refillable K cups.
Burr grind just enough of really good beans, get two uses. Beans stay fresh, cheaper than heck, and no wasting coffee. And I can use a regular K cup if a guest wants something flavored without polluting the machine.