I never use deodorant. Also don't ever use shampoo. I shower once every two days. Never get complaints. Working as a nurse, I;m always close to people who would definitely tell me if I smelled bad. Not saying this will work for everyone nor that everyone should do the same. I do however think that the industry has been successful in marketing these products as must-haves for daily use and I know that's a lie. Many people who wash regularly won't have strong odor with or without deodorant or shampoo. I did use them during puberty and I was a bit uncertain when I stopped. They work on your insecurity, and so you're inclined to keep using these products, everyday, all the time, just to be sure. No one wants to smell bad. I volunteer in a sort of day care for the homeless and the shame people feel when they smell bad and others notice is incredibly large so it makes sense people stick to their deodorant just to be sure. There's also really no harm in it, but I feel like our hygiene-cleanliness culture is quite extreme sometimes. Deodorants are a real solution for a real problem obviously, but many people over do it and when overdone people reek of deodorant or perfume. Like old ladies on a bus. Yuck.
