So I do think there’s some element of muscle-memory.  

It's the environmental protection agency. 

However, the most important element will be finding a list of non-owner occupied properties in Philadelphia and the surrounding five counties.

Doctor's office, restaurants, gyms, environmentally green dry cleaners, experiential type tenants,etc.Tenants where people can (drop and shop) and go order online for cheaper we avoid.

For example, the seller would indicate that he/she is not aware of any adverse environmental conditions on the property during the seller's ownership.

. §§ 4851-56.)According to the Environmental Protection Agency (EPA) website, you must also provide an EPA-approved pamphlet addressing lead-based paint hazards.

As the property ages, repairs become more expensive and replacement of key structural elements even more so.

I won't dispute these assertions one way or the other, but I will say that the contract used to implement the strategy is the key element here. 

Clean the water heater heating element?

You didn't mention a niche, so, I added the below links for your review and consideration.http://www.biggerpockets.com/renewsblog/2013/02/22/buying-rental-property/ (how to buy a rental property)http://www.biggerpockets.com/renewsblog/2014/01/07/flipping-houses/ (step by step guide to flips)https://www.biggerpockets.com/renewsblog/2015/01/31/ultimate-beginners-guide-real-estate-wholesaling-2/ (Ultimate beginners guide to wholesaling)To be more successful, you simply have to work on the other elements to progress your REI pursuit.