Tastytrade on their Dec. 19, 2013 Gamechangers show just put out a terrific video and thinkscript for TOS https://www.tastytrade.com/tt/shows/game-changer/episodes/8141 You may have to sign up to tastytrade which is free to view the video. The "meat" of the video starts at about 7 minutes. The thinkscript plots IV rank on the chart so you know whether it's a good time to buy or sell options. The thinkscript text attachment is on the right side of the video near the bottom. IV Rank puts context around implied volatility for the past year by ranking the current iv% compared to where it's been in the past year. IV Rank above 50% are good times to sell options. Higher ranks are even better because of the mean reverting nature of Implied vol. IV Rank well below 50% may be good times to buy options. This video introduces IV Rank: http://www.youtube.com/watch?v=y6Ev4nZElDg Many thanks to Tom, Tony and the whole Tasty trade crew for this. Also many thanks to D.C. for creating and sharing this thinkscript!