My boyfriend thinks he's pretty smart.

He just transferred all his credit card debt, which he accumulated as a dirt-poor grad student, to a new card that promised him 0 percent APR for the first year.

It makes sense. Why pay 12 or even 20 percent on your debt if you can get away with paying no interest at all?

But here's the thing -- nothing about credit cards or your credit rating makes any kind of sense, and that's why my boyfriend's otherwise sensible financial tactics may be biting his credit rating in the, um, buttock.

This is part of what I learned Tuesday night at class No. 2 of the four-part financial fitness class I'm taking (for free) from Boulder County.

And let me say, if you're not scared of your credit card company, and the people that lurk in their cubicles at Experian or Equifax or TransUnion and use some incredibly obtuse algorithms to calculate your credit score, then you haven't read the fine print.

And the fine print on most credit cards has some clause that says something like this: If you miss a payment, any payment, whether it's to your credit card, your car loan, your mortgage of even your cell phone bill, your credit card will replace that 0 percent APR with 19.99 percent faster than you can swipe your plastic through a card reader to buy that new pair of shoes.

I know. It's not fair. It doesn't make sense. But that's not the point.

The point is, when you sign up for that card, you've given away your power to people who are essentially evil. (All right, that's just my opinion, but it seems like they just sit around all day strategizing about how to steal your money with ads that say things like, "Reading this column is priceless -- for everything else, there's MasterCard.")

But here's the catch: You have to use credit to get credit for things that you really want, like a house, or a new car or a Nintendo Wii. Credit companies need to see you can pay bills before they give you more bills to pay.

So, here's the deal: Use your card -- just not too much -- pay your bill on time every single month and try to keep your debt to 25 percent of your limit. (It looks desperate, and hurts your credit rating, if your balances sneaks up on your limits.)

Here's why my boyfriend was making a smart money-management move and not a smart move for his overall future financial (and credit) freedom. If, for example, his new credit card is loaded almost to its limits with old debts, that looks bad.

And, if he closes his old cards, that shortens his credit history, that looks bad.

And if he can't pay off his debt in one year, then his interest spikes, he's back where he started... looking for a new, 0 percent card.

And if he finds one, they check his credit, and that looks bad.

So the moral? Use plastic with caution, and get out that magnifying glass -- you're going to need it to read the fine print.

Contact Camera Staff Writer Laura Snider at 303-473-1327 or sniderl@dailycamera.com.