I am also a former US Marine and separated from service in Hawaii where I lived for 10 years.  

I'm on the rental services commission and I'm frequently going back to review new legislation to ensure we're doing things correctly.

I would not keep him at $485 but I would sit down with him and tell him the other tenants were paying $200+/month more and he needed to pay at least a bit more in rent or services each year.Maybe go up $30/year and get him to help out with some more maintenance tasks or something.

Frame it as a service to them - ask if anything needs repair/rehab. 

It's more likely that people reading this would decide against using your services.  

@Walter Correia, You're going to see a range based on service level, economies of scale and geography. 

That all depends on if the rent will fully cover mortgage, tax, insurance, 5% of rental income for repairs, another 5% for CAPEX, another 5% for vacancies, and another 10% for PM services (even if you self-manage).

I agree about scaling and walking around the hood with a wad of cash is stupid but that’s what these people know that’s your clientele and you gotta  know your customer and willingly accept their flaws .

One of the reasons to enlist the services of a property manager is to insulate you from the tenants.

We also have a discounted repairs service, insurance and loan programs.