I'm known for having the nose of a bloodhound and can confirm my cat smells of expensive. (Which he bloody should do, the amount we paid for him on Preloved and the cost of his upkeep
)
I can't really explain it. It's sort of like the smell of a cold forest, with a bit of spendy leather handbag and traces of my perfume. He's what Harvey Nichols would smell like if they bottled it.
goes off to find cat to sink nose into plushious, fudgy neck fur
Anyway, loads of people talk with evangelical fervour about hair cleaning itself - there is literally no biological mechanism whereby this is possible, either straightaway or over time.
Particles from vehicle exhaust, cooking vapour, dust, aerosols, all stick to your hair and no amount of sebum production is going to magically rinse them away in an invisible cloud.
Philip Kingsley the trichologist said that leaving all this environmental pollution on your hair by not washing it, basically just means it will start to become damaged.
Unwashed hair takes on this warm mammal smell - I don't think the owners can smell it. I always seem to end up sitting on the bus next to 'no poo' fans and I don't share the enthusiasm. 