WE ALL THINK fragrance hunting is an intuitive process. But then we get to the counter and have no idea what the difference is between “eau de cologne” and “eau de toilette”. Then the questions emerge: Why are some vastly more expensive than others? What the heck are base notes and heart notes?

To help you find one that sticks, we summoned the expertise of Yann Vasnier, senior perfumer at Givaudan (the scent developers behind many of your favorite fragrances).

Here, Vasnier offers five fundamental questions a gentleman should ask himself when thinking of investing in a signature scent. Here’s what you need to know before searching for your next fragrance—which will certainly be your most compatible fragrance ever.