The only time I've ever not had my full deposit back was when it was explicitly stated in my lease that I'd produce a receipt for professional carpet cleaning before I left and I didn't bother to do so.

I think in general landlords look at the "reasonable wear and tear" clauses and consider how tenant friendly the courts are. That claim is pretty vague and it's not really worth their time or the legal fees to deal with someone if they get their back up over a handful of smaller charges.