In general, it is possible for a person who occupies a rent-regulated apartment, to become a tenant, after the primary tenant permanently vacates. This occupant is not listed on the prime tenant’s rent-regulated lease, but is either a “Family Member” or “Non-Traditional Family Member.”
Such “Family Member” must reside in the rent-regulated apartment for two (2) years or more prior to the prime tenant’s permanent departure. However, if such “Family Member” is “Disabled” or at least 62 years of age then the period of co-occupancy is only one (1) year. 
In addition, the minimum periods of occupancy are not interrupted by military duty, enrollment as a full-time student, court ordered relocation, temporary relocation because of employment, or hospitalization. 
It is important to note that such person attempting to assert succession, must occupy the rent-regulated apartment as their “primary residence.”
“Primary Residence” is defined by the New York State Tax Law as a resident who is domiciled in New York State, maintaining a permanent place of abode, and spends more than 183 days of the tax year in New York. 
Moreover, the Rent Stabilization Code provides that no single factor is solely determinative in determining whether a housing accommodation is occupied as a “primary residence.”
Evidence to help substantiate a claim that a rent-regulated apartment is one’s “primary residence” would include, such residence being listed on tax returns, motor vehicle registrations, voter registrations, driver’s license, or other documents filed with a public agency. 
The information above is intended to provide limited information only and is not legal advice. The laws relating to succession in New York are complex. If you are a party to a matter concerning succession, lease renewals, primary residency, or eviction and otherwise need further guidance in this or a related area of law, SINGH & RANI, LLP can assist you.
 Please refer to our Blog Post titled, “Succession Rights: Who is a Family Member?” for a brief overview.
 Please refer to our Blog Post titled, “Succession Rights: Who is a Family Member?” for a definition of “Disabled Person.”
 New York State Tax Law § 605(b)
 Rent Stabilization Code § 2520.6(u)