When landlords want to evict tenants, one of their nastier tactics is to wait until rent in arrears builds up to a level that would be difficult or impossible to pay all at once. This method can allow unscrupulous property owners to evict while leases are still in effect, possibly sidestepping rent-regulation protections.
If you believe this is what your landlord is doing, you can assert "laches," also known as the "stale rent" defense. The elements you must prove to be successful are:
Your landlord delayed suing you for rent. The landlord's petition is often enough evidence of this. A few judges have ruled that to avoid eviction, the tenant must only pay the first three months claimed in arrears. However, most judges require payment of between six and twelve months.
You had a valid reason to believe the landlord would not enforce a claim for the past due rent. If the landlord neglects repairs and appears to have "walked away from the building," it's reasonable to believe there wouldn't be a suit for nonpayment. Once the suit starts though, you begin to owe rent while it's pending - these current or ongoing amounts cannot be part of the stale rent defense.
Because of the delay you lost your ability to pay the back rent due. A limited bank account when the suit began can be enough to show that the delay hurt your ability come up with the money.
If your defense prevails, while the landlord may get a judgment for the full arrears, there will be a limit on how much of it must be paid to avoid eviction. When the stale rent defense is combined with other assertions, such as bad conditions or counterclaims for attorneys fees, the net result is that you can be exempted from having to pay any of the back rent in dispute.