Is performing Witr (Prayer with an odd number of units) obligatory and is it sinful to only perform it intermittently?
Witr is a stressed Sunnah that a believer should maintain. Anyone who performs it intermittently is not sinful, but they are advised to observe it regularly. It is permissible to perform Shaf` (Prayer with an even number of units) during the daytime in place of a missed Witr, because the Prophet (peace be upon him) used to do so. It is authentically reported on the authority of
`Aishah (may Allah be pleased with her) that she said:
If sleep or illness prevented the Prophet (peace be upon him) from Salat-ul-Layl (optional Prayer at night), he would offer twelve Rak`ahs during the daytime.
Muslim in his Sahih) The Prophet (peace be upon him) would, most times, perform eleven Rak`ahs during the night, offering Taslim after every two, and would conclude them with a single Rak`ah as Witr. If sleep or illness prevented him from doing so, he (peace be upon him) would offer twelve Rak`ahs during the daytime as `Aishah (may Allah be pleased with her) reported. Accordingly, if a Muslim is accustomed to performing five Rak`ahs at night and is prevented from doing so by sleep or any other impediment, they may perform six Rak`ahs in the daytime, offering Taslim after every two. The same applies if they are accustomed to performing three Rak`ahs, they may perform four Rak`ahs, performing Taslim after every two. (Part No. 7; Page No. 173) If they are accustomed to performing seven Rak`ahs, they may perform eight Rak`ahs, offering Taslim after every two.May Allah grant us success. May peace and blessings be upon our Prophet Muhammad, his family and Companions.