Analysing properties using calculator

[Adriana Mendonca]

I am newbie, I am trying to buy my first property, have been analysing quite a few deal using the BiggerPockest. It's very hard to find a property that cash flows. I would like to know if it's realistic to use 8% for repairs & maintenance , 5% vacancy( hot area in Florida), 8% capital expenditures and 6% management fees ( in house). 

Thank you in advance for any feedback!