It is implied that the methodology is fair.I always charge my tenant for water to encourage conservation and reporting of leaks. 

This article is written from a Canadian perspective but still desceibes the methodology well, recommend you check it out.

The IRS' preferred methodology is engineering-based which costs more.

Zillow even publishes their accuracy rates on a county by county basis, and they are transparent enough about their methodology that anyone who bothers to look at how they come up with an estimate would realize that it's worthless.  

The approach I use now is actually very different from the one that Jack lays out in his course (I don't use a lot of his exact methodology anymore), but he did play a major role in making me aware of the niche in the first place, and it helped me to identify what does and doesn't work well with my own personal style.Anyway - all this to say, Jack's approach is legit.

I've been using that methodology and it has been effective.

So our goal is to acquire the home/office addresses for owners of facilities in order to insure they see our mailers.My methodology so far has been to go county by county, identify all self storage facilities on Google Maps (double-checking with our database to make sure I don't miss any not on Google,) and entering the addresses into a tax parcel GIS unique to the county.

Do you have a methodology to determine basis?  

Water/sewer/trash don't change much, taxes change the most from property to property, and CAPEX can be planned with a specific methodology.  

We've delivered over 490 investment properties and greater than 90% of our clients live in other states or countries; only about ten clients were local.Back to selecting a good investment location.We developed a straightforward process for selecting an investment location that is highly likely to provide a passive income where:Rents keep pace with inflation, ensuring that you have the sustained buying power needed to maintain your standard of living.The rental income will continue for a long time.Below is an illustration of our overall methodology.