I don’t know where this “always keep a small balance on your credit card” lie came from but it needs to fucking stop.
PAY OFF YOUR CREDIT CARD IN FULL AND ON TIME EVERY MONTH IF YOU CAN. FULL STOP. THAT IS THE BEST WAY TO BUILD GOOD CREDIT.
STOP THE NONSENSE. JUST DO IT.
OMG DON’T DO THIS IF YOU CAN STAND TO PAY OFF YOUR BILL IN FULL. IT JUST MEANS THERE IS MONEY THEY CAN CHARGE YOU INTEREST ON. IT’S A TRAAAAAP.