When you're offered a "rate lock" from your lender, it means that you are guaranteed to get a specific interest rate for a determined period for the application process. This means your interest rate won't grow as you are working through the application process.
While there are various lengths of rate lock periods (from 15 to 60 days), the longer ones are typically more expensive. You can get a longer period for your lock, but in choosing this option, will likely have a higher rate than you would have with a shorter period
There are more ways to get a reduced rate, in addition to going with a shorter rate lock period. A bigger down payment will give you a lower interest rate, since you will be starting out with more equity. You can pay points to lower your rate over the term of the loan, meaning you pay more up front. For a lot of people, this makes sense and is a good deal..
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