How much 'smell' should you put into your writing?
There is no doubt that in real life aromas play a big part in our opinion of things, be it a place, an item or a person.
Personally, I love the smell of old books and freshly cut grass.
Smells can also evoke memories. I remember an episode of MASH where Hawkeye had a bad memory resurrected by the smell of a wounded soldier.
However, having read a lot of stories recently I can't remember seeing much about the smell of something. My most recent read was 'Diamond Dogs' by Alastair Reynolds. There wasn't one reference to smell in the whole novella.
I've also tried to remember how often smell comes into a good piece of writing and it's hard to think of one instance.
So how important is smell? It wouldn't seem to be too important, or maybe its use is too subtle for me to notice it. If that's the case, then it should be used sparingly.