Estimating Cash flow

[Asher Anthes]

Getting ready to buy my second property, and I want to do a much better job estimating what my monthly cash flow will be. So, first what is the best way to get an accurate measure of what the property will rent for? Zillow's rent zestimate? how accurate is this? Is there a good website that shows what nearby homes are renting for?

As far as costs, what is a good number to use for monthly repair costs? I've heard to use rent / 2 as your expense model. But this doesn't seem to be a very accurate way of calculating the profitability of rental properties, especially because you can get a pretty good idea of what PITI will be before you close a deal. What is a conservative routine repair estimate, and what is a good vacancy factor?

Finally, how much should I take into consideration the value appreciation vs cash flow potential. Obviously my long term goal is to build net worth as high as possible, but short term cash flow is essential to getting going.

Thanks for the help guys!