How long someone stays in a specific loan, either before refinancing or selling their property and paying their loan off, really depends. If someone has purchased a home or refinanced and shortly thereafter rates drop, the chances of moving onto a new loan increase significantly. During the run-up in home values, people were quick to cash-out their newly-earned home equity, and it was not uncommon to have people refinancing only months after purchasing a new home.

The average, however, is around 7 yrs for someone to stay in a mortgage--until it is either refinanced or paid off.

Decades ago, the length of time was much longer. If you look back to the 40's and 50's, people stayed in their mortgages (and their homes for that matter) until the day it was paid for. That simply doesn't happen anymore. We may be returning to those days, after the punishment that the nation is enduring, for taking every dollar of available equity in their house, as soon as the value had gone up. Lessons can be quickly forgotten, however, as evident from the US moving from the ".com bubble" to the "housing bubble," without missing a beat.