How long does it take your deodorant to stop working?

Not sure if this happens to others, but I doubt I’m that much of a freak of nature.

How long does it take for your deodorant to become ineffective? Do you need to replace it with a different brand?

Just the past couple days, I’ve realized my deodorant is no longer working. This happens after I use the same brand for about 1.5 years, possibly longer. I then have to go on a search for a nice smelling deodorant to replace it, since it will no longer stop me from sweating. I’ve tried replacing with the same stuff and it does not work.