Usually the only person that gets used to a scent is us! Sometimes we get so used to it that we put too much on because we stop smelling it. However most people are not so close to us all day that they stop smelling something. More likely they will associate one scent with you and think of you any time they smell it. That's the best part of having a signature scent! I still smell my mom's perfume when we hug, I've never grown "immune" to it and she's only used about 3 different ones in my whole life.
A lot of the people on this forum probably change scents for going out or work, summer vs winter, and so on. That way it's easy to rotate through and enjoy a larger wardrobe.