Be prepared for market fluctuations and potential challenges.Ultimately, the best approach depends on your individual goals, risk tolerance, and investment timeline.

I don't know how this could randomly change, but if your water meter is set to the wrong pipe size, it could definitely cause fluctuations in the bill.

And there is no way for you to understand what affects the market like CDOs, international politics, govt. regulation changes, misleading CPI and Unemployment reports, fluctuating interest rates, velocity of money, a fed pivot, disinflation, tax law changes and so on.  

What makes real estate seem relatively expensive is that wages and rents are down even more than home prices in real terms.All this becomes a lot more clear when you stop measuring home prices only in dollars, which fluctuate in value, and instead cross reference them against other assets, especially against other real assets, preferably those with relatively stable values over time.Hope that makes sense!

The one question I do have is how is it that the NOI fluctuates so much between the similar investments.

Fluctuating income that often comes from self-employment has been the biggest impediment to securing cheap financing.    

As Joe had mention, rates fluctuate regularly and you will likely have a different lender winner every day of the week.

Large cabins are far more susceptible to demand fluctuations than 1 and 2 bedroom cabins.  

The fluctuations of STRs can be very erratic depending on the market the STR is in and the time of year/season. 

They can crack due to temperature fluctuations (directly above the dishwasher?)