Typically, higher credit scores get lower mortgage rates and access to a wider array of mortgage products.
Extent of Indebtedness comprises 30% of a credit score and is the second largest component in the credit scoring model. In plain-speak, Extent of Indebtedness is: "How close is this person to maxing out his cards?"
The ideal percentage of credit balance to credit limit is around 35%. Anything over 70% can be hazardous.
If you are close to your credit limit on one or more cards, you can "trick" the agencies into improving your scores by moving high balances to other, "under-used" cards.
For example, let five cards at 10% of their credit limit receive portions of the balance from a 70% card.
"But my 70% card has a 2.9% introductory rate; the other cards are at 18% or more! What a waste."
That's okay -- just keep this advice in context. If you aren't applying for a home loan in the coming months, there are fewer reasons to try to boost your score and no reason to shift to your balance. I don't recommend increasing your cost of credit solely for a higher credit score.
However, if you need to get your scores up quickly, sharing credit card balances among all your cards -- even if the rate of payment is much higher -- can result in substantial savings on a mortgage month over month.
