If you’ve been trawling the Internet, trying to find information about credit monitoring services, you’re probably confused. Some personal finance experts say they’re a great idea, while others dismiss them as a total waste of money.

Why the disagreement? Well, because both sides are right. For some consumers, monitoring services can be incredibly valuable — sometimes even financial lifesavers. For others, they’re close to worthless.

A free credit report that’s really free

But before we start to explore who falls into which category, let’s get one essential fact out of the way: Everyone is entitled by law to see their credit report from each credit bureau once each year for free. To take advantage of this, there’s one website (and only one website) you must visit: AnnualCreditReport.com. Others may offer you free credit reports, but they’re usually pushing no-cost trial subscriptions to ongoing monitoring services — and you’re likely to start to pay all too soon.

Why pay for more? Credit scores

One of the big reasons for paying for a credit monitoring service is to protect yourself from credit report errors: You can’t correct those unless you know they’re there. And, as IndexCreditCards.com highlighted recently, failing to get them fixed can cost you tens of thousands of dollars in unnecessarily high interest rates — and could even prevent you getting the job you want, should they check your credit report.

Don’t assume you won’t be a victim of such errors. A February 2013 study by the Federal Trade Commission revealed that one in four Americans found errors in the credit reports that were sufficiently serious to materially impact their credit scores. If you’re thinking of applying for a major financial product (a mortgage, auto loan, credit card) in the next six months or so, you may wish to subscribe to credit monitoring in order to identify errors early, and to make sure no new ones creep in during the period leading up to your application.

Another group that may benefit from credit monitoring are those who are actively trying to rebuild their credit scores after a financial mishap — or meltdown. Seeing how your numbers are rising month by month can be a great motivator to keeping your focus on paying down balances and maintaining a perfect record for prompt payments. Having said that, some monitoring services aren’t cheap, and you may be better off putting the money toward driving down your excess debt. Alternatively, pick a less costly service, one, perhaps, that reports quarterly. Monitoring your credit score closely is also important if you are trying to raise it to qualify for, say, the lowest mortgage rate.

Why pay more? Identity theft

Possibly the fastest growing type of credit monitoring subscriber is the one who’s worried about identity theft. A 2013 study by Javelin Strategy and Research estimated that 12.6 million Americans were the victims of identity theft in 2012, and that the amount lost that year through the crime was $20.9 billion.

Credit monitoring providers say that their services can help you to quickly identify attempts to steal your identity. That could be helpful as many victims don’t discover they’re victims until they apply for new credit or receive their free annual credit report, sometimes a year or more after the first signs became apparent. By that time, the damage done to your reputation and creditworthiness can often be extensive.

Why not pay more?

So far it sounds as if you’d be mad not to subscribe to credit monitoring. So why do so many financial experts warn against them? There are five main issues:

1. Credit monitoring can be expensive. You can pay close to $240 a year, although most are less costly.
2. Some of them come with hidden fees that can make them yet costlier.
3. A lot of them don’t monitor all three of the big credit bureaus, meaning that the information you get is incomplete, and therefore sometimes close to useless.
4. Many of them don’t provide your true FICO score. And, as 90 percent of all lending decisions made in America are based on the proprietary FICO system, that lessens their value significantly.
5. None of them can warn you of identity theft as it’s happening. Really good ones may alert you of a credit application made in your name within hours of it being initiated, but even that can be too late. That said, sooner is better than later to help minimize the damage.

Should you or shouldn’t you?

Not all those five drawbacks (except, perhaps, the last) apply to every credit monitoring service. If you decide you want to subscribe to one of these services, you should certainly shop around, and find one — they’re out there — that fits these guidelines:

1. Charges a fee with which you’re comfortable.
2. Doesn’t hide away extras in the contract’s small print.
3. Covers your activity with all of the big-three credit bureaus: Equifax, Experian and TransUnion.
4. Provides a true FICO score.
5. Sends you an email or text as soon as a new credit application is made in your name.
6. Has a decent Better Business Bureau listing, and doesn’t return hundreds of horror stories when you enter its name with the word “complaint” in a search engine.

If you’re a senior citizen who’s never again likely to apply for a mortgage, auto loan or other credit, you can almost certainly rely on your free annual credit report to keep you out of trouble. Even if your identity is hijacked, it’s likely to be the credit card companies and other lenders that shoulder any losses, although you’re likely to face a whole heap of hassle and stress in resolving issues. Others, too, may sensibly decide that the cost of credit monitoring is higher than the value they could get back. But some may end up thinking that their carefully chosen credit monitoring subscription was the smartest investment they ever made.