Whenever I had a roof replaced as a homeowner, the contractor (experienced and reputable) gave me a written quote with a "subject to" disclaimer.

As long as you're offering a fair deal and have a reputable buyer, you won't have any issues. 

There was an issue with the drainage so the old landlord was having a plumber come out a blow out the pipe for $100 every month.

If you are purchasing with a hard money lender and not with all cash it does not hurt to use a reputable HML in the area that closes deals.

I wondered the same thing...I found this on CreditKarma which I've found to be a reputable site.  

Im lucky in the sense that I am a plumber and I know quite a few contractors. 

Don't jump in with both feet as it's the fastest way to ruin your reputation before you have one.

Is there a reputable property manager in town?

For me, my team consists of a realtor, property manager, handyman (for small repairs), plumber, electrician, lawn maintenance, flooring people and even a small construction outfit for those bigger jobs.  

We buy our washer/dryers from a local reputable used appliance store.