“What do you think about rates … should I lock in now or wait to see if they fall further?” Think I’ve been asked that a time or two over the past 18 years? You better believe it. It’s a good question —one that goes through every single buyer’s head at some stage.

A quoted interest rate is no good unless you’ve confirmed, in writing, that your loan is indeed “locked,” or guaranteed for a designated period of time. You need to be proactive with your locked rate as well and don’t assume that your loan officer already locked you in. In fact, your loan officer shouldn’t lock in your rate without your specific instructions. If it was locked in and rates went down you’d be pretty mad, wouldn’t you?

While neither real estate agents nor loan officers are in the business of predicting the future, it’s still possible to make a prudent choice in the face of uncertainty. Would you rather lock in your rate and watch rates fall or not lock in your rate and see rates go up?

If you decided to lock and rates go down, you’ve secured the market rate that you were happy with. But if rates went up and you didn’t lock, you’d be paying for that mistake for the rest of the loan.

There is an even worse possible scenario: After not locking in your rate, rates shoot up and you no longer qualify for the loan. So it’s important to ask yourself: “Which way would I rather be wrong?”

If you are comfortable with the rate you’ve been quoted, talk to your real estate agent about the possible consequences of waiting to lock it in.

Written by David Reed, author of Mortgage 101 and Mortgage Confidential .