I have on my desk a fancy little brochure from Proctor and Gamble telling me about their beauty research. And it contains this fascinating nugget of wisdom:
It is actually more beneficial to apply deodorant or antiperspirant at night. You do not produce as much sweat at night because your body is cooler while you sleep. The product then has time to set into your pores and work effectively the following day.
Huh. I'm skeptical, but then, if anyone knows deodorant, it should be the scientists at a company that sells it. Do you think they're assuming no shower in the morning?