Your lock will only expire if you don't get a lock for the appropriate amount of time. You can elect to lock for the entire duration of construction or stay floating until later down the road. Ultimately it's your responsibility to tell the lender when to lock you (you and your lender will discuss how that process is done and how you'll stay on top of the information you need to make an informed decision. Keep in mind, when you do a long term lock like this, lenders will ALWAYS require you to pay up to (possibly more) 1% of your loan amount as a deposit so you don't hop to the next lender everytime the market improves by 0.125%. Like stocks, you can't un-sell them once you pul the trigger. That being said, most lenders now offer a one-time float down option incase rates improve, then you can take advantage of the better rates.
At the end of the day, find a competent loan officer who can explain your options to you and set your expectations properly.
1. Builder wants me to go with their preferred lender and wants me to get a mortgage commitment from that lender.
2. Tentative closing Date is in 3 months.
1. Do i shop for Lenders/Rates now or later when i need to lock down the rates (This would be done when i get exact dates from my builder on closing date ) ?
2. If i get a Mortgage commitment now and then want to switch the lender at the time of closing , based on who gives me the best deal , is that allowed ? I understand that i might lose on the fees that i paid to get a mortgage commitment.