I never use deodorant. I'm lucky in that my commute in is with a tailwind. But as long as I shower and change shirts often enough I don't have any trouble in the opposite direction either. In the worst case, if I totally overdress I can simply wash the sweat off as soon as possible at the washroom at my destination (rather than having to take a shower). I don't see how deodorant would help in that case anyways, if I was soaked in sweat I don't think I could stand not washing up and putting on deodorant instead...