Hi Pretzel,

I used OPK once I had been TTC for a month or so with no luck. I think it is a great idea starting earlier as then you will know if you are correct with days and so on! We use to try a variety of different days as i thought I knew when I was ovulating. In the end we fell pregnant the second month of using the OPK and only DTD three times that month!

I purchased mine from the lullabye conception website as they were quite cheap and sell packs with the OPK and HPT. When I fell pregnant I gave the unused ones to my friend and she fell pregnant 2 months after using them too!!

Good-Luck