The laws governing residential leaseholds are quite involved. There are certain things that a landlord must do, and cannot do.
This is particularly true in the context of evicting a tenant from the premises. A strict and definite procedure is prescribed by law. Failure to adhere to said procedure could make the landlord liable to the tenant for damages. Landlords need to be careful, in this regard.
It is strongly advised that a written lease agreement be utilized. It serves to avoid misunderstandings between the parties; and it serves as evidence in the event that any dispute eventually ends up in court.