A cat or dog will always feel comfortable in such a carrier. Firstly, it will always carry its own scent, which for almost all animals is like a deed of ownership of that territory. Moreover, you don't need to worry about the smell disappearing after washing the carrier. Keep in mind that animals' sense of smell is tens of times more acute than humans', so the smell won't completely disappear even if you use scented detergents, although it's best to use either special products or baby detergents. For the same reason, you shouldn't rent someone else's carrier, as it will carry a foreign scent, making the dog feel uncomfortable and anxious.
