If so, and this does happen during a guest stay, how would you handle the situation? 

@Chris MagistradoRefinancing could be done in certain countries and situations. 

Assuming an only child situation where you’re not screwing a sibling.

You have provided a variety of situations where doing a cost segregation study would be useful.  

And if their both right or wrong-how to handle this situation?

Considering doing a 75% cash out refinance > 30yr 7.45% interest rateIn what situations might the 50% Rule provide a misleading picture of a property's financial health, and when would relying solely on the DSCR potentially overlook important factors? 

Real estate investing has been a passion of mine for time with my mother also having invested early on where I likely have gotten the love and desire to follow similar foot steps.I have taken last 6 months to educate myself and currently own a single family home as primary residence and would like to expand to multi family properties (2-4 units) for additional stream of income, not to mention potential tax benefits for long-term investing.Based on current living situation, I have a fair amount of equity established in my primary residency along with having enough cash to either pay off house completely or use towards investing in a multi family property.Given that I'm the sole source of income for our household with my wife being the home maker for our two kids under 2, trying to weigh out risks with getting started now or perhaps waiting. 

In my situation if I’m earning $18,000 in cash flow from a property my tax benefits are offsetting at least that amount and I’m still paying $0 in taxes so the real estate scenario is attractive to me.

Brilliant summary of the Detroit situation/market. 

There are a few things to watch for: if you are a nurse and work night shifts and your tenant has kids that make some noise, it may not be a good situation.