Pros: most convenient and accurate method
Cons: requires a teacher
The book and materials cost an initial $40, the follow up sessions cost additionally. They offer discounts to those in financial need. In the long run, it is more cost effective than pills.
This method is more convenient than sympto-thermal. Temping every morning when little ones keep you up all night was just impractical for me. This method works by adding an extra step to your normal hygeine routine and keeping a chart. It's awesome. I feel confident and satisfied, and I strongly recommend it.