As I understand, the additional 4-5 days which are added as a humra in case the lady is a zaav is a barrier for protecting from miscalculating and being over nida. My question is whether this stringent enforcement is actually permissible considering that the original law that had been practiced for centuries was that of 7 days. If one is interested in being careful and doing the nida days only, shouldn't that be taught and help out those who would like to do it? There is a concept of bringing a korban if you have been a nazir since you were ascetic and abstained from wine/grapes etc... a product that is otherwise permissible. My arguement is whether being forced to keep these extra days and causing this ascetic behavior is also a sin for those who wish to keep the 7 days only? I hope that I am not insulting anyone by asking these questions. Thank you.