I for one believe that the real estate courses I took in graduate school, as well as the courses I took as a requirement for my Brokers license, were FAR MORE VALUABLE than any of the “light weight” instruction disguised as education on social media, guru workshops, or teaser best seller books.  

don't add the extra weight, put on a good shingle get a warranty with it.

I recommend you stay away from anything within spitting distance of 38th and Post".I certainly recommend giving heavy weighting to the advice of such LOCAL experts who know the CURRENT worth of neighborhoods (as against those who try to guess FUTURE increases).ie.

If you want to know how much oil is in it put a stick or weighted string in the opening and there are conversion tables online for inches to gallons depending on tank size.

But if the skills you bring to the table are limited, or like many of us, you can’t swing a hammer without nursing a swollen thumb afterwards, then contractors it is.Good contractors are worth their weight in gold.

If you are talking about single family rentals then it depends on how many you can amass to out weight your cost of travel to inspect.

When all systems have been renovated properly (no cutting corners), it doesn't seem to cause any more upkeep than other rentals I have that are younger in age.

You will also pay insurance, property up keep, utilities, plus figure for vacancies.

An inspector is good but the engineer will carry more weight.

Also interesting to note is the NAHB arrives at their figures by applying different weight to different classes of properties.