A general rule of thumb is if your rent is below a certain threshold, currently $2,774.76/month, then your apartment is rent stabilized. Many apartments are above this threshold and are still rent stabilized for a number of reasons including the landlord taking part in 421a and J-51 tax exemption programs.
Preferential rent is any rent charged to a rent stabilized tenant that is lower than the legal rent. Uh? The law sets the amount of rent that a rent stabilized tennant can be charged but a landlord can set the rent at a lower rate.
Individual Apartment Improvements
When a landlord makes improvements to an apartment they can pass on a portion of the cost to the tenant. The increases are 1/40 or 1/60 of the cost, depending upon the size of the building. Many landlords attempt to game the system by inflating the cost of the rennovations.
This site does not offer or make any claims of legal advice. Seek out an attorney if you have questions.