For example, if I want to install new plumbing in the bathroom because the old one is old and broken, would I need a permit to do these fixes? 

Quote from @Jim Reynante: After owning properties C/D neighborhoods with high crime statistics, I have experienced all of the things that go along with it: 1) High turnover rate; 2) Tenants that don't care for the property; 3) Little/No appreciation in home value; and 4) High Crime Rate (burglary, vandalism).I am pretty tired of fixing broken windows, fixing broken doors/locks, and painting over graffiti.

Start with your primary, rent out any spare bedrooms "house hack"Use that to practice upgrades, kitchen, bathroom, curb appeal... etcNow you have experience as a landlord and flipper, use that to buy a distressed propertyAdd 40% equity to the property through home makeover, refinance into a low cost mortgageNow you are cashflowing a healthy margin on a second property, use that to build equity over time, cashout later and buy your duplex/quad.If it's going to take you 10 years to save up a down payment for a small apartment building, yeah it makes more sense to start growing your portfolio with cheap SFR flips instead.Every market is different, every borrower is different, every property is different, it would be ill-advised to recommend anything without recognizing the individual's nuanced goals and objectives with their next acquisition.

Could do I a lot less to get lower rents (for example an upgrade may be $10-$15k where a bare minimum repairs and cleaning may only be $1-2k).

Describe each and every promise they've made, when they made it and when it was broken.

Your true asset hunters are in the basement, the yard, the whole property looking for ways to upgrade the asset that others are missing.You are being very smart about your VA utilization, you just want to make sure the asset is right.

Maybe it was a hidden issue that turned into a big project, or a small upgrade that made all the difference.

I’ve found that putting in a bit of effort upfront, like when I upgraded my kitchen with discounted German appliances delivered straight to the US, makes things run smoother in the long run.

So we're now waiting on a $1.2M triplex in Atlanta that's being prepared for market or a commercial 7 units building that the owner decided to upgrade with 2 leases expiring before selling.

Are there any recent upgrades or repairs?