Best Way to Run Numbers on STR

[Matt J.]

I've gotten pretty comfortable using the BP calculators for BRRRR deals and traditional buy and holds. But what are some important things to consider when running numbers on STRs?

So far, I've been looking at properties near the area I'm looking to buy that are listed on Airbnb and VRBO to see what the average rents look like, then taking those nightly numbers and multiplying by 200 (thinking that's a reasonable guess on how many nights a place is rented within 5-10 minutes of the Gulf in the St. Pete area) then dividing by 12 in the BP calculator to figure out the monthly income. 

But then from there, vacancy, maintenance, management expenses, how do you usually calculate those, or a different way to ask, what sorts of rules of thumb do you use for these? 

Any help is greatly appreciated!