Landlords sometimes sue for possession of your apartment by claiming it's not your primary residence, and therefore you don't deserve rent-regulation protections. In that instance, you'll want to use the most powerful evidence you can to defend your rights to stay there. This includes as many tax returns with that address on it as you have, along with your driver's license or New York State I.D. card. Other strong articles of evidence are your motor vehicle registration and voter's registrations, if you have them, mail, phone bills showing usage, utility, cable and other invoices, and correspondence from government sources. The more, the better.