The facts on Fraud Alerts & Security Freezes. Both are placed in your credit files to stop people from opening accounts in your name without your permission.
A 90 day fraud alert is free and only takes a couple minutes to place at one of the credit bureau's (Equifax, Experian or Transunion). Just go to any of the 3 web sites and fill out the form. That credit bureau will notify the other two. This only is in effect for 90 days. If you have a valid police report, law enforcement agency report or U.S. postal report you can extend the period of time by submitting the above reports, plus something validating your ID & address in writing.
A Security Freeze is permanent (unless you undo it) and normally costs about $10 to file one and $10 to undo it. Each state has set cost for doing this, so check your state. You must file this security freeze with each of the credit bureau's, so it could cost you $30 to file with all 3 and another $30 to do your spouse. Transunion is presently allowing anyone to put a security freeze on their credit for free (don't know how long that will be in effect).
I place the free 90 day fraud alert every 91 days. After doing one I use a Yahoo calander reminder to remind me of the next time it's due. Works great and costs nothing but a few minutes. If you want to open an acct while you have an alert, the credit bureau will call you (for free) to get your permission. When you compare this to all the effort expended after someone gets access to you credit, it's really worth it.