Hi Kirsten,
I've been to people's home where if it wasn't for the hair on the couch or the food bowls or the cat itself, (obviously), you'd never know a cat lived there.
And others' that the smell in the house was purely nauseating, due to no fault of the cat. It's all about cat box mantinance and is not something that one can procrastinate on.
My dog doesn't smell; She cleans herself like a cat and never poos in the house, even when she gets an occasional diarrhea. Once my aunt had a cat that wouldn't clean herself at all. She was white too, and always filthy.
Some dogs smell sometimes, but i don't think all dogs smell in general.
Usually it's the dog food or lack of bathing that makes a dog smell. Although it could be a hormonal thing too. My dog rarely needs bathing, unless she plays in the mud or gets into my lipstick.