Lease dictionary
Duty to mitigate
The landlord's obligation to try to re-rent your unit if you leave early - not just bill you.
In most states, a landlord whose tenant breaks the lease must make reasonable efforts to re-rent the unit ('mitigate damages') instead of letting it sit empty and charging the departed tenant for every remaining month.
Once a new tenant starts paying, your liability generally stops. You owe the gap - vacant months plus reasonable re-letting costs - not the whole remaining term.
Watch out
A lease clause saying you owe all remaining rent 'regardless of re-rental' contradicts the law in most states. Don't take it at face value.
See it in action
The Notice to vacate letter puts this term to work for you.