My daughter and her room mate had to pay for all new carpeting because of one little stain. I don't know why they couldn't just replace the area that was stained. They only had a six months lease and the rest of the carpeting was perfect. They lived in St. Louis, MO.
Depending on where you live, and what the rental laws are where you live, they shouldn't have to if it is just natural wear and tear. Did your friend take pictures when they moved in and out? This is usually a positive mark for you to show to a judge if you go to court over it. It would show the carpet, walls, and the general conditions when you move in and out. Even if you go to court now, the landlord might win this one if you don't have the pics to show the difference. There is a landlord/tenant board in your city I would expect, go and talk to them, they might be able to better inform you than I can. Hope this helps, good luck.
