"They're not going to take stupid risks. They're not going to reduce the loan-to-value just to get the client," Schmitt says. "But they will take money off -- (for example) 25 basis points off your mortgage if you also open a checking account. If you do direct deposit to that checking account from your employer, you get another 15 basis points."
A basis point is one-hundredth of 1 percentage point.
"For that client who is willing to provide them with that multiproduct relationship, they do (offer incentives)," Schmitt says.
Plastic proposals proliferate
Credit cards are another big product your checking account provider may try to sell you, says Kathleen Day, a spokeswoman for the Center for Responsible Lending.
"There are a lot of come-ons now about how you can transfer your balance on your credit card and have a zero percent interest rate for a year," Day says. But those offers often come with hefty fees that don't make it into the sales pitch.
"You have to read the fine print," Day says. "Don't ever be afraid to say 'no.'"
There's one big reason to be careful about taking out loans or signing up for credit cards at the same bank that holds your checking account. Most checking agreements contain a clause that allows the bank to draw out funds to satisfy debts you owe to other divisions of the company. For instance, if you have a delinquent credit card balance, your bank may be able to drain your checking account to pay it off.
If you have a deposit account with a bank you owe money to, when the debt comes due, there's substantial legal precedent for allowing the bank to take the money out to cover it, says Justin Hosie, an attorney and partner in the Tennessee office of the law firm Hudson Cook LLP.
Roper says in the end, the choice of whether to purchase an additional product or service from your bank should come down to the individual qualities of what exactly it is selling.
"You may decide that while you like them perfectly well as a bank, their fees aren't competitive for their other products," she says.