When you pay it off, you can use it again and again. ( it should go without our saying, I’ll say it anyway.... pay off the dang card) The power of the line of credit, is having resource available and ready to deploy immediately and repeatedly.

Dang the good old days when I didn't have a worry in the world.

You will pay a higher premium for that privileged.Now I am not speaking as an insurance agent but President of Illinois REIA.As a Chapter of the National Real Estate Investors Association we have access to online quote service that does list billing and invoicing in arrears.  

But they dont pay for about 30 to 60 days after invoicing.

Just the action of showing all tenants all usage led to a > 10% reduction in water usage on the next quarterly invoice from the utility.  

If your GC friend intends on invoicing you for the work and paying subs and suppliers, then he probably needs to have a license and should research the state requirements.  

If you can show invoices from a company and checks payable to that company, you don't have to do this.  

If this happens for a while, and you elect to try to evict, the judge will (likely) say that you accepted partial payments, and in doing so have agreed to take the partial payment in lieu of pull payment (regardless of what your lease says rent should be).I elect to use an electronic service that invoices the tenant, and requires that VERY EXACT AND PRECISE amount to be paid. 

Or you can do  a rent Roll by running an open Invoice Report and it will show you who is late and how much they owe you.  

I was selling some stuff I had lying around the house... they didn't like it and took away my account because I wouldn't provide invoices for where I got the stuff.