While on a shopping spree, you open credit-card accounts at several of your favorite department stores to snap up discounts of 10% or 15%. You’re saving a bundle, but you may be chipping away at your credit score.

Minimum FICO credit score requirements for store credit cards are different for approval from store to store. While credit card companies do not disclose their credit requirements, we can estimate credit requirements for a particular card based upon surveys of previous applicants’ experiences applying for the particular credit card.

CoreLogic and FICO partnered last year to offer lenders an alternative credit score for more predictive scoring, which includes data previously not used in credit scoring, from a borrowers cell phone bill, utilities, payday loan activity, to child support judgments, evictions, property tax liens, the status of homeowner’s association dues, whether or not a borrower is underwater on their current home, or whether a borrower owns other properties that credit agencies typically miss.

FICO isn’t the only number used to determine your credit risk — the score that counts is the one your lender uses. There is no single credit score number — the compilers of the widely accepted FICO Credit Score allow lenders to customize their system, so different lenders produce different scores.

A credit score is either a blessing or a curse cast down upon you from the digital cloud. A score of 740 qualifies you for the best interest rate on a conventional mortgage. A score under 640 means ugly interest, and a number under 620 makes it very hard to get a mortgage at all.