Heck, lots of people move because they are living in a bed bug infested building and want to escape, not realizing that they are bringing the bed bugs with them when they move; this is another aspect that the Philadelphia law fails to recognize.

I've done door to door for 3 pest control companies.

I plan on installing some form of termite protection after purchasing anyway, but is there anyway to make sure I'm not buying a house with a full blown infestation that could become a bigger issue?

Utilities, taxes (property, local vacation, & income), landscaping, furnishing / decorations / amenities, pest control, & supplies (soap, TP, etc) are the big ones on my STR calculator that you didn't mention.I'd also recommend using the enemy method to determine expected income.

The cost for a tenant to move from a great landlord and home is significantly higher than the 5% so they will stay and probably say thanks.If the previous year had some drama at the home the tenant wasn't responsible for such as a flooded basement, leaky roof, rodent infestation, noisy neighbors, etc.... you may get some push back on the increase and the excuse they need to move.  

Purposely infest the place (if possible ) with some fast breeding bugs, then watch them WANT to get out as fast as possible :) You could hire someone to do this for you maybe :) 

I sell pest control so I am always inspecting houses throughout the county. 

Sometimes both.Your HOA may cover pest control, but that's something to consider.Regular Maintenance - within the 1st year on a new build, you shouldn't pay for anything.

Also, did you have a pest inspection done?

We inspect the properties to find unauthorized pets, look for pet damages, pest control issues (fleas,) and problematic yards (feces or digging,) so we keep a portion of this as well.