Should I get a "lock-in"?  

A "lock-in" is a written promise by your lender that the loan terms (rate, costs, etc.) will not change due to market conditions for a limited period of time. In almost all cases, if you are reasonably satisfied with the interest rate and terms your lender is offering you, get those terms locked-in, in writing, at the time of your loan application, for at least 45 days or longer. Many people make the mistake of "riding" the interest rate roller-coaster after applying for the loan hoping for a lower rate near the time of closing. Since the pressures for interest rates to go up are always much stronger than for them to come down, rates very seldom come down, and then, not for very long at all. Trying to time this is pure gambling at best; foolish (and expensive) at worst.

The purpose of a rate lock-in is to protect you from the pressures for rates and costs to increase. Since interest rates are very sensitive to all types of economic news, any piece of "bad" news causes an instant rise in interest rate costs. Since Wall Street seems to thrive on "bad" news, it is always just around the corner, usually about the time for your loan to close. Our advice: get a lock-in, in writing, for at least 45 days, and don’t worry about the interest rates; you’ve locked-in a good deal.