I am a little confused. So I have read that on a cheapie opk a faint line means nothing but I always get a faint line in the few days before I o. Cbfm tells you your most fertile days- gearing up to o. (Correct me if I am wrong). So isn't that the same as a faint line on opk? How does the cbfm tell you when you're gearing up to o but the regular opk doesn't? Sorry if this is confusing or a dumb question. I only used opk's one month when ttc ds so I am definitely not an expert on the things. 😊