4. Make sure help goes both ways. As much as the Smiths helped the Hewsons by paying the mortgage in their first home together, they never felt like they were being taken advantage of, because they also came out ahead financially. That's because the Smiths handled all of the utilities, including cable, gas, and electric bills. That meant the Smiths could delay tapping into their retirement funds, while still affording regular cruises around the world. Plus, whenever they did decide to travel, they had built-in babysitters for their dog.
5. Know when to say goodbye. For the Hewsons and Smiths, that day might never come. But for William LeFavor, it made sense to move out after he could afford to buy his own house. Says his father, Phil LeFavor, a retired high school vice principal, "We said, 'You can stay as long as you've got a plan.'"