That's precisely what I do...I also advise not closing the accounts once they're paid off, keep them...All mine pay me to use them, but each uses a different "category"...I use the one that pays me the highest percentage for each category - such as fuel, groceries, restaurants, etc...It's only pennies per purchase, but they add up...In my case it's several hundred untaxed dollars per year, as opposed to paying them interest charges amounting to thousands of my dollars which are left over after I paid taxes on them...That means we're using the credit card company's money, interest free, for up to 30 days at a time, but since we pay off the balance before any interest comes due, it doesn't cost us anything to use the cards. In fact, we earn the annual maximum cash-back bonus on a couple of our cards every year. So they are actually paying US to use their money - interest free.
In addition those old CC accounts are valuable to your credit history as the age of your credit accounts affects your score...I check my scores from all the sources frequently (I also get alerts on changes) and they hover around 820's to 830's our of a possible high of 850...The one that matters most to me comes from my bank, it's consistently right at 837...Not bad for a guy who hasn't had a job in the last 17 years and lives within a Social Security income...
But I still don't have any Triplelocks, just 142 other S&W's and zero debt...
