You could also survey some local property managers and explain the house you are buying, the area, and say you're thinking about renting it out down the line and find out the vacancy rate for them.Many BP members mention the 50% rule which is 50% of your rent will usually go toward expenses (including vacancy).

I have been doing my research on BP for sometime now and have been following some best practices.I am asking all prospects to fill out a pre-screen survey prior to scheduling a viewing.

Set it up with your PM to do this for you.We use resident surveys for move-ins, move-outs, and maintenance calls.

The biggest thing that sellers trip up on is removing objections - if you do all the above and then your buyer stops short of offering because they are nervous of the survey or they are short of capital they will not offer.

We typically spend 30 seconds on a rent survey, then post the advertisement at the high end of the rent range while it's still occupied to gauge how many responses we're getting. 

It is a cash offer and the seller doesn't have the survey.

Survey fed.

Also, get with a great realtor and PM in the area to survey the market and see what areas you can launch your strategy in.  

And I was able to do this on my own, spending only $480 on the renderings (included below), not including the application fee which was an additional $360 or survey which I had done about 2.5 years ago for $625.

This is an informal survey for a presentation I'm doing.