Abu Hurayrah (ra) has reported that the Messenger of Allah (ﷺ) said,"Hospitality extends over three days and what is beyond that (more than three days) is Sadaqah.  

قَالَ رَسُولُ اللهِ ﷺ الضِّيَافَةُ ثَلاَثَةُ أَيَّامٍ فَمَا كَانَ بَعْدَ ذَلِكَ فَهُوَ صَدَقَةٌ