Any building constructed before January 1, 1974 with six or more apartments should be rent-stabilized. There are exceptions to this rule, but if you live in an older building with six or more units, and your landlord has not given you a rent-stabilized lease, it’s worth your time to research your building’s history.
Landlords are required to register rent-regulated buildings with an agency called the Division of Homes and Community Renewal (DHCR). If you go to your borough’s branch of DHCR with a lease or valid ID, they will give you a document called the rent history, which will tell you whether the building was registered as rent-stabilized. If that sounds like too much legwork, just email them.
Unfortunately, landlords do not always register their rent-stabilized buildings with DHCR (remember what I said about them being the worst?). If DHCR does not have any record of your building, consider these other options.