I have mixed feelings about my MB. I found it pretty useless at first but after spending the money I thought it may be a good idea to invest a little time in some experimentation. I used it morning and afternoon every day for a month (after not eating for 3 hours). I found that the morning results were the closest match with my temp chart. The problem with using it in the afternoon is that I was getting ferns almost everyday. In the mornings I never actually get the full display of thick ferns like the sample on the leaflet but I do get the most ferns about 2 days prior to O. I wouldn't just use MB on it's own but with my temp chart it's ok. I also found best results for me are if I follow directions & it's dry after 10-15 mins not sooner no later. Ahhh the things we put ourselves through!