What happens if my tenant vacates prior to 30-notice as stated in the lease?

I am not sure if NJ is 30 calendar days or if notice is due by the 1st of the month(I was landlord in Alaska and that was our policy.) They were in a month-to-month and had to give you 30 days notice. If you want to be the nicer enforcer, add 30 days to when they gave you notice and then prorate it. They owed through the middle of March, about half the rent would be $625. I would send them a certified letter to their new address or, if you don't know it, mail it certified to the address with you and it should forward. If they don't pay, take them to small claims court with the lease, THE EMAIL most importantly, and you will win. You may even be able to claim for the rest of the month if you couldn't rent it.