'A'isha reported that the Messenger of Allah ﷺ used to observe Witr every night, and he would (at times) complete his Witr at the end of the night. (Using translation from Muslim 745c)
مِنْ كُلِّ اللَّيْلِ أَوْتَرَ رَسُولُ اللهِ ﷺ فَانْتَهَى وِتْرُهُ إِلَى آخِرِ اللَّيْلِ