I know, you're probably thinking "how stupid is this chick?" but I have a valid reason for asking, I promise! :) I started using the Clear Blue Easy Fertility Monitor and in the instructions, it mentions something about not charting Day 1 as Day 1 unless you started your period early in the day. So I called their customer service number to confirm and she did in fact say that if you start your period any time after NOON, that you should count the following day as Cycle Day 1. So, just wondering what you've been doing, what you've been told, etc. A day can make a difference in the charting/TTC/ovulation world as we all know! Thanks!