The best deal doesn't always come in the form of the lowest interest rate. Rates can vary between lenders and brokers, and fees can also vary between lenders and brokers. I believe it would be in your best interest to work with 1 broker or lender that you have worked with before or has come to you as a referral. If he or she is a competent lender, they will explain to you how rates are determined, how rates can change day to day, how paying points or not paying points may be best for your situation, and when is the best time to lock the rate. There are many, many facets to mortgage lending that can differ between lenders and brokers, and can vary for borrowers. Don't be afraid to ask the lender how they get paid and how much they will make on your loan. Also, ask for referrences. Full disclosure is important and often overlooked aspect of a good lender/broker. The bottom line should be that you get a loan that will close at the time you need it to close, at the rate that you locked, and at the fee you were quoted.