Discontinuing a habit of voluntary Sawm

Q 4: I am accustomed to observing voluntary Sawm (fast) for three days of every month. However, I sometimes get so tired that I cannot observe such a Sawm. Am I sinful for not observing it? Is the reward of the previous observance of Sawm recorded for me or does abandoning this Sawm decrease the reward? Is it obligatory on every person who observes Sawm for three days of every month to do so regularly?

(Part No. 10; Page No. 387) A: You will receive the reward of the previous Sawm you observed. Moreover, you are not sinful for abandoning voluntary Sawm.May Allah grant us success. May peace and blessings be upon our Prophet Muhammad, his family, and Companions.