Probably ...
New jersey
Is it legal for the landlord to submit a new estimate of damages to property on the day of court in a counter claim, after the initial itemized list has been given to the tenant in the 30 day time frame
It is not illegal to update the estimate of damages but it may cause judge to scrutinize the list closely.
Some damages may not be visible until work has begun. For instance if the carpet appeared stained or torn, that estimate may have appeared on the first list. Then when the carpet was lifted to repair and re-stretch, the padding and flooring underneath may have been discovered to be damaged. For damages like that, the landlord may with evidence be able to persuade the judge that you do owe for them. For damages that should have been apparent as soon as entering the room, you may be able to persuade the judge were done after you left, if you have photos of the rental after your move-out. If the original was an estimate, the landlord may have received estimates from contractors since the original estimates were sent and the actual work estimates from experienced contractors may have been higher than the landlord hoped they would be.
