I currently have 5 MCs and Visas, which I used to run at 75% util. Three of the cards have $20k lines, one $15k, and another $10k. Never missed a payment, but six months ago I decided it was time to start paying for vacations, car repairs, and home appliances w/ cash.
Fortunately, I always had the cash to pay off the balances, but developed a habit of using the cards in the 2000's when they had much lower interest rates.
Over the last few months, I've cut the balances to 30% in aggregate, with only one PIF. I have the cash to wipe out all the debt, and use the cards far less than I used to. I put $10-$20 a month on the PIF card, just to prevent an inactivity cancellation.
I'm now preparing to pay off the other 4 cards, however, I want to keep them open. My question is how much do I need to charge on each card per month, or per year, to prevent a low activity cancellation? Do the cards w/$20,000 lines need more activity than the one w/$10,000?