Most owners are happy when a below-market rent-stabilized or rent-controlled tenant surrenders possession. However, when the rent is above or near the market rent, a vacant apartment can remain empty for a long time without any rent being paid. So, owners should be careful that they do not release tenants from the balance of the lease when they vacate and abandon the premises before the lease expires. The law is that an owner has no duty to re-rent the apartment before the lease expires (that is, no duty to mitigate its damages). The lead case is Holy Props. v.
Many tenants treat their landlords as banks where they can get interest-free loans. These are the tenants who chronically refuse to pay rent when due. They take advantage of the delays in the legal system to hold off paying the rent for as long as possible. Trying to get these tenants to pay rent on time costs owners time and aggravation.