Is Your Landlord Overcharging You? Legal Limits on Security Deposits

As a renter, you know what your price range is and what you're looking for in an apartment, but do you know your rights? Last year when I was apartment hunting in Brooklyn, I was shocked to learn that it was possible that a potential new landlord might ask for 6 months' rent up front for my security deposit (luckily that didn't end up being the case, but still!). I'd always just assumed security deposits were always an additional month or two months' rent, sometimes a little more if you had pets...