Does paladins need to concentrate on their smite spells after they hit?

@JeremyECrawford Is the intent that paladins need to concentrate on their smite spells for duration of the spell even after they hit?

— Simon Lantz (@Shippendale) January 1, 2016

Some smite spells, such as wrathful smite, do have an ongoing effect that requires concentration. #DnD https://t.co/dpvJqraE6y

— Jeremy Crawford (@JeremyECrawford) January 5, 2016