As I see it, he owes you December, January, February, and March. So... $1200. $900 at the least, if you concede that the rent ran from the 20th to the 20th of each month. $300 due on December 20, $300 due January, $300 due February, and then $300 for vacating without 30 days notice (March).
Whenever you have no written lease, it automatically defaults to a month to month tenancy. With a month to month, either party mus give one month's notice to terminate the agreement. So he also owes you for March- $1200 is what I would sue for, plus any other fees, cleaning and turning the space over.
As for when the rent was due, it would be when it was customarily paid. If he was paying on the 20th, then it would be the 20th.
So even though we didn't have a written agreement the 30 days notice is the law?
The renter was trying to say that his rent started on the 20th and not on the first when he got the keys....we figured he was paying one month behind and he says he was paying one month ahead...
He owes you for any time he had possession of the residence, if he could have moved in on the 1st... he had possession on the first.
As for paying ahead or behind... it doesn't matter. Just add up how long he was there, and add up how much money he gave you. That's it. It is not as complicated as you are making it. If he moved in on June 20 and moved out on Feb 10 (for example), he owes you $2100 total. Subtract what he paid you total, and he owes the difference.
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