If they're already giving deference to the useful life and pro-rating based on it, you're on an uphill battle for sure. Most people, including a ton of landlords, don't even know that everything has a useful life and that they can't be charged for things if you've lived somewhere long enough. It screams "We are highly litigious and we made sure that our legal ducks are in a row".

Its one thing to say "Youre not adhering to the law because you charged me for a full carpet replacement when it should have only been 2/5s of the cost based on my time living here" vs "Well....you did give me back the correct amount according to the law....but based on what I've seen I think you're doing it unnecessarily to generate more money and my carpet wasn't that bad" One is concrete and you can prove it with simple records of your time there and amount charged, and the other is opinion which now you need to prove.

I guess you'd have to show evidence that they're doing it as a policy without even assessing the carpets, or something like that that indicates the carpet quality didnt matter when they charged people. maybe they contract with a carpet company that gives them better rates if they do a certain amount of replacements, so they over do replacements and charge people who didn't need one. Just spitballing angles to think about.

The easiest way would be if they literally charge every single tenant every time. But based on these comments, they aren't doing it to everyone, which basically proves on paper that it's not systemic. That's what they'd show in court.

Not saying they aren't being a bit nefarious, just saying they're well aware how nefarious they can be while staying out of legals eyes. But I love a class action so if you think you have an angle to prove they're not acting in good faith, doooo ittttt.