See also this BP topic that describes in detail some of your observations.

. - well, maybe shingles are different, but my observations seldom exceed 20 years with shingles, so, 20 years is good enough.My experience is that contractors that do not have the capacity to perform well are more than happy to charge more than their skill and performance is worth and the uninformed consumers of those goods and services are willing to pay the charges - no longer by me.As to the price being the same for a rehabber as any other customer, that may be true for you and your business model.

A few observations.1.

Hello, home inspection came back for a 1977 home that state:"Observed a galvanized water supply line in attic over master bedroom was heavilycorroded appears to be leaking.

Here's some of what I have observed during my time. 

Nothing is more telling than seeing how a tenant will act in the future by actually observing how they are living in the present.

It seems pretty simple to me to observe the cost of equity capital on syndications and see that it is far higher than the cost of equity capital in the publicly-traded equities market. 

The outside observer can see it!

Partnerships founded only because neither has all the money to do on their own have a higher failure rate.Just broad stroke observations.  

Same goes for work / school, though what people make on their time shouldn't be your business (provided they pay).If the tenant is clearly communicating a problem (ants), given the observations above, I wouldn't be surprised if she has not received proper information on how to resolve the problem.