This was my first cycle using OPKS and I thought it was really interesting! I really had no idea whether glow had predicted my cycle correctly or not but I have to give credit to glow for being so spot on with my AF as well as ovulation. I'm very regular with my cycles. My cycles arw only 25 days. If anyone has any questions about OPKs you can ask me. I know when I first started using them I would post stuff asking for questions and no one really answered but I'd be glad to help :)