If you fast the six days of Shawwal, you do not have to fast al-Ayyam al-Beed during that month too and hopefully you will be rewarded for that.

There is no sound hadith to indicate that there is any special virtue in fasting in Rajab. But there is a report from the Prophet (peace and blessings be upon him) which indicates that it is recommended to fast during the sacred months. For more, please see the detailed answer.

Singling out one day of the year for fasting, in celebration of Mawlid al-Nabi (the birth of Prophet Muhamamd), is an innovation (bid‘ah) that is contrary to the Sunnah of the Prophet. For more, see the detailed answer.

Whoever fasts on the day of `Arafah or `Ashura, and still owes some days from Ramadan, his fast is valid. But if he has the intention of fasting this day to make up for a missed Ramadan fast, he will have two rewards – one for the day of `Arafah or `Ashura and another for making up the missed fast.

1- It is recommended to fast three days each month, and it is best to fast al-ayyam al-beed, which are the 13th, 14th and 15th of the month. 2- There is nothing wrong with you fasting three days in Sha’ban, even if some of those happen to be in the latter half of the month.

Fasting on the day of ‘Arafah is a confirmed Sunnah for those who are not performing Hajj. It expiates for sins of the past and coming years.