. >> reporter: peter grabel helped them get the mortgage, and says many of his clients are opting for arms over fixed-rate loans. >> the average mortgage in this country is paid off in less than seven years. so, for whatever reason, most people don't stay in the mortgage longer than that. so if you have a arm for seven years and your rate is lower, you are ahead of the game. >> reporter: in 2005, near the height of the real estate boom, adjustable rate mortgages were almost 40% of all home loans. as housing went south, that number fell to about 2% in 2009. freddie mac predicts arms will be about 7% of mortgages this year. before you take out an adjustable rate loan, it's important to understand the drawbacks. fixed-rate mortgages have equal payments over the life of the loan. arms, on the other hand, typically offer a teaser rate for a set period of time and then adjust annually. there's been one big change since the real estate bust: it's much harder to qualify for an arm now. before, buyers didn't always have to document income. mortgage strategist mahesh swaminathan says that chang