Account for equity when paying down loans

[Sean Mills]

I am planning to purchase my first rental property this coming winter using conventional financing. While I save for a downpayment I have been analyzing properties for practice. When looking at properties and the return they will generate, should I account for rent paying down the mortgage and building my equity in the property while doing my analysis? Is this something that is just nice to know, or should I be factoring it to my decisions?