Deduct for Cap ex/repairs etc. before or after paying Mortgage

[Nathan Patterson]

Over the past few months I've been practicing my hand at analyzing. Basically I'll find a property on the MLS and then try and estimate rehab costs, do research to estimate the rental amount, how much to set back for cap expenses etc.

Usually when I analyze these properties I deduct mortgage/interest first before deducting money for cap ex, repairs, insurance etc. Reason being is because the PITI of a property is going to stay mainly fixed over it's life while the rest could be flexible.

My question is this, what do you do?  Do you deduct before or after paying debt?  I feel like this is an ignorant question but maybe others are wondering the same.