Let 1-9% of its CL report if you have more than that as a balance pay it down to get it in line.
If you are playing the util game, you want less than 10% to post on one card to give you the maximum boost. If you're not apping for anything, then there's no point in it. Just PIF and don't pay interest. I like mine at 0% because it means I'm not paying interest. FICO doesn't like that, so I lose a few points. But if I want a bit of a boost for an app or something, I'll let a small amount post on one card.
FICO has no memory of useage. So I only do it when I want to.
July 2013 score: EQ FICO 819, TU08 778, EX "806 lender pull 07/26/2013
Goal Score: All Scores 760+, Newest goal 800+
Take the myFICO Fitness Challenge
Current scores after adding $81K in CLs and 2 new cars since July 2013
EQ:809 TU 777 EX 790 Now it's just garden time!
June 2017 update: All scores over 820, just pure gardening now.