I've been handicapping for 40 plus years and manage to drive a profit almost every year. I mainly handicap pro and college football and some college basketball. Those sports for me are the most likely to profit from by doing your home work. I started my first book in 2006 and have progressed through the seasons as rules change and margins of victory change, so does my book. I keep my numbers up to date in case of a major change in power ratings. I wouldn't say it's the only tool to use, but one you need to start with before evaluating a game.