Interesting topic
I find this interesting, to be honest.
Mixing or combining scents is challenging, but I believe you need to have a real sense and also aptitude in combining successfully different perfumes. To me, not everyone can do that with success (in the same sense that not all people have a 'creative' approach in decorating successfully their apartment/house or combine successfully various items in their day dress code, for example).
In addition, I heard sometime ago that there are no male or female scents or perfumes; as a result, one may mix/combine scents freely.
However, and under a general context, it is much more difficult done than said, at least for me.
For example, would you ever mix two different after shaves? And if yes, which would these be? You may say of course that "Why should I mix? Tabac AS or D.R. Harris AS (or whatever else) is fine as it is..." Sure, it is, but variety is the spice of life...