I pay asap, but I require invoices that make sense.

A couple of weeks later we heard from our neighbour: the City had sent him an invoice for tree trimming.

I have not yet paid cash which amounted to more than a tiny percentage of our net worth for a vehicle.FYI - look up the invoice amount using Edmunds, Kelly Blue Book, or whatever, and do not pay a penny more.

If they say they don't take credit cards, they can set up a free Pay Pal account very quickly, and then send you an invoice which you can pay by credit card. 

If you were my client, you'll see their invoices when I bill you for the work.

-All invoices from sub contractors come directly to me, in which I pay them directly (no mark up).

Solution: Have contractor sign agreement to take pics wkly and submit them wkly w/an invoice early in the wk.

I keep all my documents, invoices, bills, leases, everything scanned and saved in digital format on my computer, and cloud-backed up to a service that allows me to access all my files over a smart phone app or on the web from anywhere anytime.

@Michael Dang, the class B and C didn't sour when the O&G market dropped like an anchor.

With today's technology / computers, it is much simpler to do and we use some of the same terminology for the same / similar concepts.Think of it this way, if you were running a business where you have many repeat customers to who provide a service or product (e.g. flower shop, pool cleaning, HVAC maintenance, whatever), you would not have a separate bank account for each customer but you would have to keep track of what each customer has been invoiced and what payments they have made.