I'm neutral on whether or not to have one of those services. A lot of them are legalized scams to get money out of you, and as others said, they don't PREVENT credit fraud; they just tell you it happened. The most important thing to do, in my opinion, is to check your credit regularly yourself. The actual site is annualcreditreport dot com; NOT freecreditreport (like the dumb commercials). You can check all 3 bureaus, and you can opt out of all the subscription crap. If there's something wrong, they show you how to start to fix it. But be patient; it's not going to get fixed overnight.
But the most important thing: DON'T put yourself in a position to ever need "emergency" credit! Any successful businessman will tell you that they never rely on credit. Young inexperienced, impatient business people will go get all kinds of loans and credit cards so as to look wealthy. Not a good start, and you'll get caught with your pants down if your credit gets ruined, and you need it suddenly. Have enough $$$ on hand, that if you do get hit with credit fraud, you can pay all your bills and pay off any credit card balances that get skyroceted interest due to the fraud, then fix the problem patiently before using your credit again.
If everybody thought this way, there would be no economy catastrophe, and nobody would be in foreclosure!
Charles