Late, Messy Tenent / Roommate

[Jon K.]

I am both the landlord and roommate, dwelling in a house with multiple roommates.

I have a few questions:

1) Tenant has paid, but been late with rent every month.
I have not yet assessed the late fee ($30) that is specified in lease. Should I? Tenant pays a few days late each month, but less than 5 days late (after 5 days, I accept certified check, at my discretion of continuing lease or not). Should I always assess late fee no matter what? What problems have I caused by not assessing late fee?

2) Tenant has caused damage during move-in. About $500 worth.
I have not yet billed them or repaired (it's flooring damage- aesthetic, but not a vital repair). How should I handle the repair? Tenant said their uncle would fix it. How long should I give them to repair it? Should I have my own contractor out to fix it, then send them the bill? Do I notify them of my intent to repair and send them the bill? (The lease states they are responsible for all damage.)

3) As a roommate, the tenant's messiness is a concern. It is leaving storage items out throughout house for months, or leaving dirty dishes out. As a landlord, dishes aren't a problem- but as a roommate, cleanliness is important to me. How do I balance being a roommate and a landlord?

4) Can I do a landlord check after the person has already moved in? Would that be completely pointless?
I made a huge (HUGE!!!) mistake by not checking previous landlord references. The tenant did invite me over to previous residence to select furniture for our home, and property was messy-- did not appear damaged. Tenant said they had never been late on rental application. Is a landlord reference check a moot point after move in? Should I do a check now to see what I've gotten myself into? I'm curious if tenant had been late every month at previous residence like they have been here. Am I allowed to do a landlord reference check or credit check after move-in? (I would imagine that I could, but since I approved them, they moved in.)

What would you do?

Is a few days late on rent every month reason to terminate someone's lease (my contract/lease gives me that option)?

Is it worth going to that extreme? I am most worried about regular late rent, as well as damage. As a landlord, I would prefer tenants who pay on time and keep property clean and without damage. As a roommate, I would prefer a roommate who is clean, pays on time, and is a better roommate match for me (clean, pays on time, picks up after themselves, quiet in common areas).

I am also worried about how this tenant affects my other tenants, in terms of cleanliness, noise, etc. I'm both a roommate (housemate) and a landlord, and am having a hard time balancing both.

Any advice for a new landlord/roommate?