I was doing it at night using "calming bath" with the idea that a warm bath, then feeding would get LO ready for sleep - quite a few ladies on here do this. But my LO hates being naked SO much that the bathing experience consists of screaming while I scramble to finish before he breaks his lungs LOL... So for me, I usually bathe in the evening since OH is there and can help (LO gets quite squirmy too) - hopefully I can get a bedtime routine with bathing eventually when he is older.
But I would say whatever works for you is best - it is different for everyone!
xx