Just over 10 years ago I had 14 revolving account, of which 7 were credit cards.
today I have only two credit cards:
One is Citibank, purely for airmiles. Never keep a balance, paying it about weekly.
Interest rate is 13.5 or so, but the annual is high
Other is at 8.9% and only use it for foreign transactions. At 1% FT charge, its cheaper to use the card than exchange cash or withdraw it overseas.
On the score, my debt runs 22% and plan to just pay it off in the next month. Shall see what difference it makes

Cheers