Renter pays late rent every month. $50 late fee included

[Joe Lujan]

I inherited a rental from my Mother in law with a tenant that has been there for about 12 years. He pays his rent inconstantly and was behind $100 dollars. She collected rent by check sent to her address. Always late. I put him on contract with a security deposit and late fee imposed. He was late as expected on the first month so I served him with Pay or quit notice. He paid the rent due and back rent. He has not payed security deposit yet. He said he will pay Security at end of month and pay regular rent which is due on first, on the 11th. I told him that a $50 late fee will be imposed as well. He acknowledged this. He and the rental are registered with COZY so he will pay on line. My question on this forum is, How many times do I allow him to pay late, even though he pays the late fee? I'd rather get paid on time instead of an extra fee! What do I do if he doesn't do as he sez?