How often can you reuse ground coffee?

It depends on what you use it FOR.

Seriously—when I forget to change it even within the hour, the hot beverage result LOOKS like coffee but weaker than tea and not fit to drink.

For drinking, ground coffee can be used once. You might be able to re-use it for something else besides drinking—like to get epoxy or gorilla glue off your hands after its used—or for a facial scrub or maybe its good for the plants.

Coffee grounds go in my garden

I use it twice – sometimes even a third time. if I do use it a third time I will add a little instant coffee to bump of the flavor and caffeine levels.

After I use them up I let them dry on my wood burning stove and toss them into the fire when dry. The heated, dry grounds add a little humidity and a nice aroma to the house.

The only way I see this as feasable is if you dry them and regrind them. Still, the times I have tried this the coffee was so horrible that it was undrinkable.

My palate is so poor I can’t tell the difference. It always tastes like milk and sugar.

I can’t use them a second time without adding to the grounds.

We have a small 5 cup coffee machine and I use 1 scoop per pot and if I decide to have another cup or two I will add 1 or two scoops to what is already in the pot before I brew.

Otherwise it is a weak, bland, watery brew; little better than colored water.

It drink it black. If there are ingredients other than coffee and water it’s not coffee, it’s a coffee based drink.

I mix old coffee grounds into soap, or dump them in my garden.

Twice. Once to make coffee and another to fill the garbage can.

Once for coffee, once for compost. That’s it.

If I was desperate to get a cup of coffee and had no new grounds but had old, I might try steeping it for an extended period.