Stabilization, which applies in buildings built before 1974 that have six or more units, as well as in those that receive certain tax breaks, means that your rent can be increased only by the percentage set each year by the city’s Rent Guidelines Board. This year, it’s 1.25 percent for one-year leases and 2 percent for two years.

To find out if your apartment is rent-stabilized, request its rent history from the Division of Housing and Community Renewal.

When someone moves out of a rent-stabilized apartment, the landlord can raise the rent by up to 20 percent, plus a portion of the cost of any improvements made — one-fortieth or one-sixtieth, depending on the size of the building. If you see an increase on your rent history that doesn’t seem to add up, you can seek a rent abatement by filing an overcharge complaint with the Division of Housing and Community Renewal. There is a catch, though: With few exceptions, complaints must be filed within four years of the increase.

Apartments typically fall out of regulation when the rent hits a certain threshold (currently $2,733.75) and the regulated tenant moves out. If you live in a stabilized apartment and your rent surpasses that threshold, your increases will still be governed by the city. But once you move out, the apartment will enter the free market.

Preferential Rent

A preferential rent is a discount given by your landlord for a set period, as defined in your lease.

When landlords offer a preferential rent, they also list a “legal rent” — the real stabilized rent of the apartment. Landlords have the option at each lease renewal to end the discount and raise the rent to its legal maximum.