I had been using another app to track my cycles, but never felt it was terribly accurate, and became annoyed with the chipper advice and the social media aspect of it (polls, silly message boards). Then I read Taking Charge of Your Fertility, by Toni Weschler, and I liked the idea of that tracking system, but didnt want to bother with paper charts and different colored pens. I was so happy to find this app! Its easy to use and so far, has been accurate. One thing that would be nice is a way to track fertility treatments (distinguishing regular intercourse from IUI, for example, or taking into account the effect of an HCG shot on your peak day). Not sure if that is even possible. But the app does provide space to add custom notes for those types of things.