My back ground::: I have been primarily a Heavy Diesel Mechanic most of my life.  

And when you pay the invoice, in the Memo line of the check, reference the invoice number you're paying and, assuming you are paying it in full, write "Paid in full" or "Final payment" to keep Mechanics Liens out of your life.To avoid confusion, I tell my contractors before they start that they will be getting a 1099 from me at the end of the year and collect the required information right then.

But your stop-loss mechanisms save you on the trades you lose, and your profit happens on the trades that go the right way. 

You didn't need to be a visionary to look at the primitive steamboats on the Hudson and see sailing ships days were numbered or see how the early farm mechanization would change agriculture.

How are mechanicals?

This will avoid any 'mechanics lien' surprises. 

I have wanted to buy my own truck for years now but I am not mechanically inclined by any means.

@Jesse Mitchell for the most part mechanicals have little affect on the market value.

I would suggest trying to learn some of the simple stuff via YouTube or some basic home mechanics books you could get from the local library. 

I would say if all mechanical systems are working, there's no leaks, and some sense of integrity in performing the work: then someone could potentially be ok not completing all the fixes required to make a place market ready and rent for cheaper.