"I'm on hormonal birth control and I'm interested in switching to FAM. When should I start?"You've done your research, read the books, talked to other people who use FAM, and you've made up your mind that you want to give it a shot. Maybe you are on hormonal birth control, have been in the past, or have never been on it. No matter the situation, a question that comes up often in my DM's and in Facebook groups that I am a part of, is when do I start charting?