So most investors just throw in the same expense factors no matter the age of the property.

All North DFW has the highest appreciation while South DFW will be giving you the better cash flow.If this is your first rodeo, then I would suggest to be close home if you are also planning to self-manage.Then the age of the properties and access to highways.

It also serves as a great example of what I tell my college age daughters - email/text is a very hard place to have serious conversations without at least one person getting rubbed the wrong way by what can be inadvertent phrasing by the other party. 

Only "CASH OUT" of your IRA in cash of an emergency or you are at retirement age. 

The house's age isn't so important as the age of the systems in the house.

Further, we need to account for a $10k “reserve” for what will be repairs / maintenance as the property ages.  

Some of my Scottsdale connections who specialize in land deals have been whispering about how a few smaller outfits in Casper.. from what I’ve heard, outfits tucked behind older storefronts, have been matching buyers with off-market parcels that never even hit the usual channels.If you line up your financing carefully (no legal or tax advice here, just speaking from experience), you can sometimes lock in a deal that ages nicely over tthe years.

@Chris Seveney & @Jay Hinrichs Together you raised a good topic of discussion which is the new age Co-GP.

One of the biggest pitfalls is the age of the buildings I'm looking at. 

Maybe he does file a nuisance mechanics lien (whether he can and precise procedures) will be dependent on local law.