Agree with the second floor. I always suggest clients to secure a one year builder mortgage interest rate once they signed the purchase agreement. When it's 120 days and 90 days before closing of the new home, your mortgage specialist should let you know if the special mortgage rate is higher or lower than your secured builder rate. If higher, then there's no point to change again. If lower, you can get a reduced interest rate. This is the best practice for all my clients. Hope this helps