I figured that if I had a credit card bill of $10,000, why should I pay off that bill to the bank from my savings when I could open another credit card account and have another bank pay off the bill for a year? That way I could leave my $10,000 in my offset account and reduce my mortgage interest. In effect, one bank was paying off another bank's loan and I was reducing the interest on my mortgage. Clever, eh? Keeping the banks honest. Making sure they were being competitive. Voting with my feet. What could go wrong? I employed my strategy cautiously. I always made sure I never rolled over more than I had in my offset account. If for some reason I had to pay it down, I would be able to without incurring more debt. I always made sure I would roll it over before the special deal rate expired to avoid interest. I would never use the card to make purchases as that would trigger immediate interest payments on the total amount. I would pay the minimum amount on time. I would always shut down the card as soon as it was off the interest-free period to keep a lower total credit limit when applying for a new card.

It worked seamlessly for more than three years and saved me real coin. As the end of one interest free period neared, I would check out the latest offers online and apply, making sure there were no ongoing fees or transfer fees and that I had approval well before the end of one interest-free period so I could roll my outstanding bill from one card to the next. But last time I applied for a new card, the bank queried my application. They didn't say no to my application, they just wanted more information from me citing my credit rating. It piqued my interest. Using a free online credit check service, I applied to see my credit rating. Let's be clear. I've never defaulted. I'm not a bankrupt. I have been employed full-time for 20 years. I have merely followed the mantra of successive governments whose unwavering advice has been to find the best competitive offer.

So what did I learn? My rating had been pummelled. On a scale from 0-1000, excellent is considered 800-1000. Very good is 700-799, good 625-699, OK 550-624 and below average was zero-549. My rating was 588, or OK, and came with this comment: "This score indicates moderate risk to many lenders. They might expect a proportion of people in this category to have serious problems repaying credit." It turns out that every time I applied to a credit-card provider for a new card, they would inquire of the data base as to my credit worthiness. And while those inquiries did not raise concerns to stop a card being issued, the mere inquiry from a financial institution would stay on my credit scorecard and affect my rating.

Sure enough, it contains details of four credit card applications during four years and a pre-approval application I made for a mortgage from a competitor to my bank, made to ensure I was getting the best deal. Five listings, no context of whether I was a good or bad customer, yet a stain on my credit rating because I've tried to get the best deal, just like the advice said I should. Those marks will stay on my credit rating for five years until they are rolled over. In a system where the major financial institutions have significant pricing power, credit score cards can feel like they're stacked against customers trying to encourage competitive behaviour. Trying to get one back against the banks comes with a cost, and it's not always in the fine print.