How to determine damages with smell

[Josh Darley]

BP,

I went to do a final walk through today after a the lease expired in a SFH after two years. The house smelled absolutely horrible, a little bit of cigarette smoke and a lot dog pee. We had visited the property only a couple times over the last year (lesson learned), and it did not smell this way. We had an idea the tenant was a smoker, but were under the impression that she only smoked outside. The carpet needs to be replaced as not only does it house smell horrible, but there are a few tears that do not look repairable. The carpet was nowhere near new, so how would I determine how much she is responsible for versus how much of it was on me. Is that just a useful life calculation? Aside from the smell and the couple tears, we would definitely not be replacing it before renting again. How would I go about proving that the smell is so bad that it needs to be replaced. The photos of the tears would not warrant replacing the whole thing, but the smell definitely would. How do you go about proving something that is subjective such as smell?

Thanks,

Josh