I'm currently looking at properties throughout the Fresno, CA area.  Specifically looking at multi-family units and will be looking to purchase 1-2 properties this year.  My first rental property was something decided out of necessity and not as an investing decision, so I was looking for any advice for estimating expenses.  I've read about the 50% rule, which seems like a good rule for doing quick analysis; however, as I get to the point where I need to start making offers I was hoping to get some input as to how everyone estimates their expenses.

There are some things which will be easy to calculate such as the mortgage and property taxes, but is there a set percentage people set aside for repairs?  Vacancy?  Also, does anyone in the Fresno area have a rough idea of insurance for a 2-4 unit property?  Thank you!

-Josiah