@Branka-and-Silvia0 Both dogs and cats can leave strong odors. With cats, it's usually because there is a litter box or because "cat people" often tend to have several 🙂
Some dogs smell quite "doggy", particularly if they don't get bathed often enough. I happen to have a dog that is virtually odorless, guests and friends have commented on it after petting her- "Wow, my hand doesn't even smell like dog- she has no dog smell". But in the rainy season here, when her fur is always a little damp, she really reeks and requires frequent bathing.
Homes with carpeting and lots of upholstered furniture retain pet odors, even if the animal hasn't urinated on the carpet or anything like that. Places with hard surface floors and just some throw rugs which get washed won't hold the smell.