They're sales people not experts by any means, many times I have asked for a fragrance and they don't even know what it is. 2 recent ones I remember were Guerlain Vetiver and L'Homme. There were 2 ladies when I asked for GV and they both had no idea what it was, until 15 second when one thought she knew what I was asking for and she finally found it. That was at a Macy's. The L'Homme was at Perfumania I believe, with a 24 year old guy. I had to point out multiple times where it was on the shelf and he finally picks it up and bam, he drops it on the ground, luckily it didn't break. He inspects the bottle reading the name and continues to spray numerous times all over himself in rapid fashion telling me that it smells great. These are just 2 experiences, almost every time I have to say the name numerous times and point out on the shelf where it is.
Then there were the exceptions, E'toile I think thats the name, in the Houston Galleria, has a very knowledgeable SA that can get anything at an instant and can also recommend frags based on what other frags the customer has or likes. I'm sure there are a few fragrance enthusiast SAs that work at department stores, I don't want to give the wrong impression. I feel so much better with these people because once you call out an uncommon gem they know where you stand, they wont go pushing the latest Hugo Boss or Diesel Only the Brave on you.
Lets face it they are paid to sell, they see what frag alot of people like and they recommend that to everyone. To the common nose, almost every fragrance smells good. And there is the fact that people buy frags based on the Brand, bottle, and color of the juice.