Breaking a lease - obligations

Probably a case by case basis. Read the lease. But in general I would guess they can charge you whatever because you are breaking the lease Whether or not someone else comes right in or after 2 months is independent of you leaving early.

It depends on where your apartment is located. In Brooklyn, Queens and Staten Island, a landlord is usually required to mitigate damages by making reasonable efforts to find a new tenant. If you found a satisfactory tenant (good credit and meets landlord's other requirements) then you might get hit with a fee of some sort but shouldn't have to pay the rest of the lease. In Manhattan and the Bronx, however, an appeals court ruled in 1997 that the owner has no obligation to mitigate. I do recall, however, that despite what the lease says, if you want to assign your lease to another person, the landlord has to consent if the request is reasonable - what is reasonable is a case by case analysis, but would look to credit-worthiness, etc. I would start by asking your landlord, especially if you have a good replacement tenant.

Any expenses that the landlord would incur with the new tenant taking over the lease should be paid for by the original tenant on the lease.