If instead the building is owned entirely by a single person/entity adding, an additional unit is not relevant to TICs or HOAs.

@Lucas MoralesThis is my own personal opinion, with owning over 1,800 units.

As it was mention before you're walking a thin line when taking a house sub to and then dealing with the bank to do modifications.

Personally, I own 137 doors and am happy to weigh in!

I am currently house hacking and renting my basement through my LLC. 

I have a neighbor right next-door to me whose house is in pretty bad shape.

You’ll probably end up having to pay any buyer’s agent a commission so you’re really trying to save 1-2% max on your seller’s agent before you pay for advertising, professional photos, doing the open houses and showings and paying to be on the MLS.

Reading up on Montgomery County, MD but can't definitely tell - When does a house hack fall into an ADU? 

@James Sillshere is a plan for you1. stay in whatever job you can make the most money in2. go to RE meetups and build a network3. save up enough to house hack, then house hackgood luck

You do not and can not toss a general rehab number based on sq ft at houses.