DEAR BOB: My husband and I own five rental houses together. We are very happy you encouraged us, years ago, to invest in rental houses. By making extra mortgage principal payments, two of the rental houses are now free and clear. The others will have their mortgages paid off in a few years. We now enjoy the positive cash flow from the rentals. Meanwhile, the houses have appreciated at least $100,000 each in market value. My husband recently had a "close call" with a heart attack, but he had a bypass operation and is now in good health. more...