“I happened to see my dad run for governor when he was 54 years old,” Romney said. “He had good advice to me. He said never get involved in politics if you have to win election to pay a mortgage. If you find yourself in a position when you can serve, you ought to have a responsibility to do so if you think you can make a difference, and don’t get involved in politics when your kids are still young because it may turn their heads.”
There has been a minor stink online about this quote, but he's not incorrect. In order to run for office, you need significant cash reserves in order to provide for your lifestyle -- family, etc. Running for president, or even Congress, doesn't include a paycheck.