In the most part, we don't always get told exact dates of new arrivals. However, for some TV seasons Netflix do announce when new seasons will be made available. Here you can find a list of known seasons updates, and brand new exclusives, coming soon to Netflix USA!
For posts announcing new additions, removals and expiry dates please follow NewOnNetflixUSA on Twitter, Facebook or Google+. They are only posted between 9am and 11pm Eastern time so they shouldn't be missed while you sleep.