This is my first month temping and using the OPK which I started on CD8. It is now CD14 and I have only had a very slight line appear on CD12. We have been at it like rabbits since as my temp hase only risen v slightly. How long would you recommend testing for?
It depends on how long your cycle normally is, but I would keep testing. If not, you may have missed it (well not if you have been at it like rabbits) as pos opks can last for under 1 day.
Good luck.