If your landlord aggressively pursues every means to throw you out of your apartment, then when you pay rent every month, send the check by certified mail and make sure the checks are being received and deposited. If Post Office records show the mailings are being rejected, or if the landlord isn't depositing the checks, follow up with correspondence to the landlord asking why this is happening. Otherwise you risk the landlord surprising you with a claim the rent was never received, and commencing eviction proceedings against you. An alternative is to bring the payments to the landlord's office and get a receipt for them. This isn't always practical and some tenants are uncomfortable encountering an intimidating landlord every month. With certified mail, you'll have physical proof you sent the rent in on time. It's inconvenient, but sometimes necessary in order to protect your rights.
Attention New York City Tenants: Get more information on eviction at the McAdams Law main site here: