How often should you review your credit report

A good strategy is to spread out your requests throughout the year, instead of getting them from all three agencies at once. Every four months, request a report from a different agency; that way, you'll be able to check your report three times a year, for free. Look for old or inaccurate information. Also check for anything that looks fishy-it could be a sign of identity theft.

This is from a legal website