Base it on tenant quality more than anything.  

Everything on the estimates were the same quality GAF roofing and materials.

I believe common sense if a rare quality trait with people these days. 

However, rental rates and quality of tenants are high too. 

As an Interior Designer/Project Manager who’s done Home staging I’ve  had to work with flip houses that lacked forethought and or quality execution for some realtors trying to market that basic “lipstick on a pig” approach and I wish their flip investors had called me from the planning phase…You may not need an Interior Designer to oversee every step of a renovation but what I’ve been asked to stage after poor choices in style, colors and materials it can be painful. 

Then you can pare down who you listen to to higher and higher quality sources of information. 

Tenant Quality - is it located in a market where the tenants are employed, stable - versus so transient that a 30-day stay is considered normal (and you can't make money with those).3. 

Notices and and cause being required or not is thicker if they've been there more than a year.Not sure if $850 Is worth it, but I would say yes if this is a quality RE, tenant and contract focused attorney and landlording to you is more than a hobby. 

@James Parla The price depends on the type of study you have done as well as the quality and services that come with the study.

I believe my judgement may be clouded by the fact that I have had zero decent quality tenants apply in over a month and have had trouble filling the vacancy.