Credit agencies can help people improve their credit and save money, but they can also cost consumers their most private information.

Financial planner Paul Oster says companies like Experian Boost require access to savings accounts, checking accounts, money market accounts and more to boost an individual's score.

"They're trying to look at how you manage your money, which could be a good thing," Oster says. "My problem with that is we're sacrificing our most sensitive data. We're sacrificing our privacy."

Experian Boost could be helpful for young adults without much credit history because it allows them to get credit for utility and phone bills.

Oster says those are the accounts that people are most likely to pay late.

"The ulterior motive is they just want to collect more and more data and then sell it or share it with other companies," Oster said. "And that's a problem."

Those who do sign up with Experian Boost can go back to their old credit models or revoke their permission at any time.

It's important for users to do that before their bank accounts get low or they miss utility payments.