Best to change diaper just before baby is abt to sleep. When you see baby looks sleepy, can change. And change maybe 10 mins aft baby wakes up to let him pee first (if diaper is not heavy) . If baby wakes up late, and you feel the diaper's heavy, then slowly change it with wet wipes. Nxt diaper chge then can wash with water.
No need to change during the night:)