Narrated by Uqba bin Aamir (RA), ‘I heard Allah’s Messenger saying:
One of my followers gets up at night pushing himself to perform ablution (for prayer). On him there are several knots of Shaytaan. When he washes his hands, a knot loosens. When he washes his face, another knot loosens. When he passes his wet hands over his head, yet another knot loosens. When he washes his feet, the last knot loosens.
Then Allah (SAW) says to those beyond the eyes i.e the angels “Look at this slave of Mine who cures his inner self and asks Me for forgiveness so what he asks is given to him.”
(This hadith is sound and reported by Ibn Hibban and Ahmed in his Musnad.)
Personally, I try to make wudhu before going to bed, apart from the Islamic benefit, the cleanliness and hygienic benefit is good too. Besides there’s the odd nights when you cant fall asleep, can easily grab the Quraan or other kitaab to read for a while.