We have been ttc for 5 months now, this month makes 6. I finally decided to order some OPKS and I'm so glad I did. I've always had pretty regular cycles (28-29 days) and for the past few months we went by the fertile week this app and another showed with no luck so far. Well, I ordered the Wondofo OPKS from Amazon and started using this cycle. I was very surprised to see that I had my positive on CD12 when these past 5 months I thought it was CD 17/18 like the apps showed me. Of course I know an app cannot tell what is truly going on inside your body, but we still used it as a general window. So, for any of you ladies not using OPKS I would definitely recommend purchasing some. Good luck to you all :)