It was narrated from Ghudaif bin Al-Harith that he asked Aishah (RA) in which part of the night would the Messenger of Allah ﷺ perform Ghusl? She said: “Some times he performed Ghusl at the beginning of the night and sometimes he performed Ghusl at the end.” I said: “Praise be to Allah Who has made the matter flexible.” (Sahih)