When to Apply 50% Rule

[Joseph Herring]

Hello everyone, 

From what I understand the 50% rule is a general rule of thumb for estimating monthly expenses and cash flow for owner-occupied multifamily rental properties. My question is:

Does this rule apply for multifamily properties that are not owner occupied and/or single family rental properties? Also, could it be that the math is the same but the 50% can be adjusted for each case to be a more accurate estimate? What would you use instead and why?

Thanks for the insight!