I realize this is highly subjective with a lot of variance, but there must be some average square footage per living unit that one could baseline 'cramped' units against 'spacious' units in an area.Local building code?

For example zoning calls for 6 stories, but city planners have seen several applications result in 9 stories.So we use what's exactly written in the zoning code for the property, pick the best use of the land that would net the best result. 

Effective January 1, 2018 the Occupational Code was clarified on advertising stating that the salesperson or team name cannot be larger than the broker’s name.

I've been remodeling for 20 years and know the codes well enough that I'd be comfortable doing it under the radar, but that's some major stuff. 

I even helped write a few of the first energy codes when Berkeley was working on it.

I’d like to connect and partner with a real estate agent that specializes in rental properties, a CPA that specializes in stock market and rental investing tax codes, and anyone else that loves investing, financial independence, and early retirement (FI/RE). 

The inspector missed that there was a window pane that was entirely unsealed and that none of the smoke detectors had dates written on them and that 4 of the 7 (long story as to why there's 7--the fire code changed) were dead. 

Any poor condition, frayed or altered knob and tube wiring should be replaced.

As always, refer to your local code when constructing bedrooms and place safety over money in every situation.

Stabilization, doors, zip code etc.