Illustrative example
Someone has rented month to month in an outer-borough apartment for four years with nothing in writing. The owner sends a text message saying to be out by the end of the month.
For a City monthly tenancy the landlord must serve a written notice stating that they elect to terminate and that, unless the tenant leaves on the day named, summary proceedings will be begun - served in the manner in which a notice of petition in summary proceedings may be served by law. For residential tenancies the period comes from § 226-c(2), and four years of occupancy puts it at ninety days. The text message fails on both counts, form and length.
They agree a leaving date four months out, the owner puts the notice into proper form in the meantime, and the tenant gives access for viewings in the final month.