Lenders are required to give additional information about the score, including the four factors, or reason codes, that hurt it the most. A fifth factor can be added if one of those factors is inquiries, or the number of times potential creditors pulled your credit score or report. Not all inquiries count the same, however.

For example, if you shop around for a mortgage, auto or student loan, the FICO score will ignore inquiries made in the 30 days prior to scoring, according to myFICO.com. Inquiries older than 30 days that were made within any 14-day span or 45-day span, depending on the version of the scoring model used, count as one inquiry.

There are also "soft inquiries" that don't affect your score, says Bradley Graham, senior director of product management at FICO.com. That includes when you or your employer pulls your credit report. Ditto with marketing offers you get in the mail.

"It only counts when you initiate requests for credit," Graham says.