The most sound financial practice for retirement money over 45 years is to invest for long term capital growth, to avoid taxes. But that produces no income, so they refused my mortgage. I decided to be daring. I started calling other banks, explaining my situation before applying for the mortgage. I finally found one that agreed to be creative, and consider my bill payment history, savings record, college degree, etc. as indicators that I'm a good risk.
ARMs are cute.
They're a way of getting magically low interest rates. But after a few years, just when you've forgotten about it, the curtain is pulled back and the Wizard is revealed as a charlatin. Your interest rate jumps through the roof, and the bankers pour themselves another glass of Sherry. The bankers are at it again. He who has the most points win.