We don't really need them all the time. I understand the act of wanting to always feel refreshed and smell good, but do we even know the risk some these products pose to our healths?
Deodorants are mostly chemicals applied to the body to prevent odor caused by perspiration due to bacterial breakdown - antiperspirants which are used to block sweat by affecting the sweat glands are the most common form of deodorants. This means that very strong chemicals needs to be involved as part ingredients for a substance to qualify as deodorant. Aluminum is one very constant chemical in almost all antiperspirants.
Aluminum in antiperspirants appears in the form of Aluminum Chlorohydrate. It's been proven that the presence of aluminum in the body at high doses, adversely affects the bloods brain barrier and can also cause epigenetic effects due to it's capability of damaging the DNA. This is just one chemical and the damaging health risk it poses to the body. They are at least half a dozen different chemicals in every deodorant which have their different effects on the body. Some have even been connected to diseases like breast cancer, kidney dysfunction, etc.
I guess my point is, we don't have to always use deodorants all the time since they pose some health risk. We can simply find ways to limit our constant use of them. For instance, we can skip their use when we're indoors or aren't going out to undertake hectic task which leads to perspiration. Little things like this might just make a difference. We can never be too careful.