I have two, and have SUCH a hard time wrapping my head around having 10, much less 25, 100, or more!
I like having a "signature scent" -- one for warm weather, and one for cool weather. I definitely prefer to smell the same every day, and I think DH likes that there's a scent that smells like "me." (I have also learned the hard way that DH HATES many of the citrusy scents I love -- so when I find something I like that he also likes, you can dingdangity well bet I will wear it until the bottle goes dry.) On the other hand, if you like to wear fragrance like clothes, more power to ya.
The two I have are my warm-weather scent, which is almost gone (Gucci Flora Eau Fraiche), and the cool-weather one I'm getting into now (Estee Lauder Pleasures).