Every re-heating. And I am not counting drops. If the drops were laid out end to end they'd be two inches long in a batch less than 6 ounces. Stabilizer cooks out and the smaller the plastic quantity the faster it departs. While some insist that adding this much stabilizer affects the plastic, I have not seen a change in the plastic I use at all. I am using stabilizer sold by the same company that sells the plastic to stay uniform.