I remember seeing this method in many popular books and podcasts.However, the STR world has changed so much ever since with its exponential market growth.

You can also check online resources like BiggerPockets or Roofstock, which offer general CapEx guidelines based on property type and age.These methods should help you perform a solid preliminary analysis.

Here are a couple of methods of pipe replacement that I am aware of you might be interested in looking at.https://www.youtube.com/watch?

But that is also in the very nature of real estate, it is long-term.

Now let's look at Quality based on grade of wood.There are primarily two different terminologies and methods to grade Quality. 

Check out this BP article about how they come into play with the BRRRR method.

From talking to locals, there's a couple of issues than need to be addressed, some are the non-ecological practices that some of those developers have, unfortunately, our government profits from this investors and allows them to destroy manglers (which are the natural water purifying system of that area) dismantling hectares of mangroves and degraded the habitat of resident and migratory species burying animals alive.There's proof of fecal material floating beneath the city of Tulum, only 20% of the water is sent to the water treatment plant, there's no infrastructure for the exponential growth.The landfills in the middle of the jungle that is leaking hazardous pollutants into the freshwater system and that something that developers won't tell you.I love my country and it would be a disaster for everybody if this place ends up like some other great beaches around the world, that are completely ruined by greedy investors not following the rules.There's no urban or comprehensive master plan, and one of the risks is that Tulum will be like Playa del Carmen is today, overgrown and with environmental devastation.I will advise doing a lot of research before getting something in Tulum, different country, different rules, and practices.

@Elizabeth RossFor properties under 100k you will likely need to use the BRRR method as its difficult to get a 30Y loan on a properties valued under 100k.

I recommend an electronic payment method.

Strategies like house hacking, the BRRRR method, and long-term rentals have worked well for me.