Musannaf Ibn Abi Shaybah

Hazrat Aisha (may Allah be pleased with her) said: Except for three days, it is permissible to perform Umrah throughout one's life; on the Day of Sacrifice and the two days of Tashreeq, Umrah cannot be performed.

Hazrat Tawus was asked about Umrah, so he said: After the days of Tashreeq have passed, one may perform Umrah for the coming year whenever one wishes.

Hazrat Ali (may Allah be pleased with him) says that there is (one) Umrah in every month, and Hazrat Saeed bin Jubair says that there is one Umrah in a year.

Hazrat Ikrimah says: Perform as many Umrahs as you are able with the razor (whenever your hair is sufficient for shaving, perform Umrah).

Hazrat Anas bin Malik (may Allah be pleased with him) used to perform Umrah from Makkah, and whenever his hair became suitable for shaving, he would set out for Umrah.

Hazrat Ibn Umar (may Allah be pleased with them both) used to perform only one Umrah every year, except in the year of war; in that year, he performed two Umrahs, one in Shawwal and one in Rajab.

Muhammad considered performing one Umrah in a year to be better.

Hazrat Qasim disliked performing two Umrahs in one month.

Ibrahim says that (most) of the Companions used to perform only one Umrah in a year.

Hazrat Hajjaj says that I asked Hazrat Ata about performing two Umrahs in one month? He replied that there is no harm in doing so.

Hasan preferred to perform only one Umrah in a year.