I have three credit cards. One has a $4300 limit, the other $4000, and another $2000. I barely touch the first two because I prefer the rewards of the $2000 limit card. On that card, I probably have a running balance of around $1400-1600 at any given time, because of the payment timing (always pay it off). I know they say keep you credit usage around 20-30%, but will it affect your score if you focus that in one card?