When did your DC (or would you expect) switch from evening baths to morning showers?

[MTCV]

DS has SN, so any new routine has to be introduced gradually and way before necessary if possible! Trying to work out when I should introduce the idea of a quick shower in the mornings rather than (or as well as) a bath/shower in the evening.

He's 12. He uses a deodorant. He refuses to use the (communal) school showers, and it caused a huge fuss with the other kids so I definitely don't want him to be in the position of being known for a smell!
He won't wear clothes twice so has at least one clean shirt a day. Today, as usual, he came home with muddy legs so definitely still needs an evening scrub.