Landlord is making me pay for new carpet. (apartment, lease)

[Quicklysinking]

Hello. I'm needing some advice. I moved out of my apartment about three weeks ago. I got a letter from my old landlord telling me i have to pay for new carpet since i had a pet in the apartment and the pet could have pee'd on the carpet. I did have a dog in the apartment and paided the $200 pet deposit and the 15 dollars a month extra. I called the landlord after receiving the letter and they told me the deposit was not going to cover the whole amount to replace all carpet since i had a pet and they had to change it. My carpet was not torn but was very lightly stained after living in the apartment for a year, and the carpet was not new when i moved into the apartment This is a pet friendly apartment and they do not change the carpets after every move. But the landlord claimed to change the carpets every time someone moves in with a pet. My question is, why are they charging me the full amount of replacing the entire carpet in the apartment? When it was not explained in the beginning before i signed the lease and there is nothing in the lease that says when you move in with a dog you have to cover the entire carpet expense. If that was the case i would never have moved in. Any advice would be helpful. Should i get a lawyer to fight for this cause or pay the $600 and get over it? It there anything i can do?

[reenzz]

You are required to pay the depreciated value of the carpet plus any damages to the subflooring due to pet damage.

[Floorist]

They have to prove how long the carpet has been down. You have to pay the depreciated value. Carpet generally is depreciated out after 7 years.