I like to use data, coming from an engineering background, and I see the data and trends over history, this can be used as a guide only to help with investment decisions (it’s not a guarantee but another tool to use). 

., roof repair, window replacement, floor replacement, painting, etc.

He watches some flip shows with me but still gets disgusted by dirty carpet (even when I point out it's only a $2000 replacement expense).

I'm an engineer by degree so a methodological, data driven approach was important to me.  

Now in most cases the same renovation will require an engineer report, and full architectural drawings….I recently had to obtain structural drawings and complete special inspections for a rear trex deck….Just a few examples of costs someone will incur flipping a house in Philly.

Well here's what we ran into, David:You by and large need white trim if you're going to do cheap vinyl replacement windows, any sort of easy quarter-round on the floor.

We had to replace multiple floors of carpets, paint the whole 2 floors, fix doors, fix broken drywalls, baseboards.

It's a bit cheaper and you will be replacing it in a few years anyway.

I have to replace an egress staircase from the second floor which was originally made from pressure treated wood.

These tenants reported the wood porch floor being damaged, and since it is old, I replaced it with brand new boards.