Ordinarily, your landlord is required to give you notice of changes in your rental agreement a certain period of time before the change goes into effect (typically, at least 30-days notice). Whether you were on a month-to-month during 2012 or a lease that terminated at the end of 2012, January 2013 would be treated as a month-to-month tenancy requiring the minimum notice period. For your landlord to win this one in court, he/she would have to prove that you had agreed to pay additional back...