In how many days the Quran should be recited

It is narrated from Abu al-Aliyah (may Allah have mercy on him): "Sayyiduna Mu'adh bin Jabal (may Allah be pleased with him) would not recite the Noble Qur'an (in full) in less than three days."
The chain of this report is jayyid (good), and Imam Musaddad bin Musarhad recorded it in his Musnad.

Abd al-Rahman bin Abdullah bin Mas'ud (may Allah have mercy on him) narrates from his father (Sayyiduna Abdullah bin Mas'ud (may Allah be pleased with him)): "Sayyiduna Abdullah bin Mas'ud (may Allah be pleased with him) would (on ordinary days) complete the Noble Qur'an from one Friday to the next (once a week), and when it was the month of Ramadan he would complete the Qur'an once every three days."
The chain of this report is sahih (authentic), and Imam Ibn Abi Shaybah recorded it in al-Musannaf (3510).

It is narrated from Abu Ubaydah (may Allah have mercy on him): "Sayyiduna Abdullah bin Mas'ud (may Allah be pleased with him) would recite the entire Qur'an and complete it once every three days, and he set aside very little time for reciting the Qur'an during the daytime."
Ibn Abi Umar recorded it in his Musnad.