Basically common contract or agreement law.

In a city like Philly, you will face many challenges - you need to learn the market and know the neighborhood and the block and make sure all of your numbers are within reason, you need very reliable contractors, you need a to understand the permit process, you need to be familiar with market expectations. 

While we faced minor delays with contractor scheduling, strong project management minimized impact.

Expect a custom ADU to take 9–18 months, with 3–6 months for design and permitting and 6–12 months for construction, depending on complexity and contractor availability, and the speed of processing permits.

As a licensed contractor, I can provide insights to make sure you’re getting the best value and quality for your project.

Hiring a contractor to assist with repairs and a property management company to manage rental.

Quote from @Kody Smith: without getting too deep into my finances, what my strategy is...1. take loans to buy properties (leverage)2. fix/flip for day to day cash flow income3. use some of the fix/flip income to buy consistent cash flow through:- business acquisition, - commercial properties (MF and store fronts),I have no intention of doing ALL of the management myself, I will hire management as needed (medium term goal)my expected core role is money provider, evaluating the numbers, making decisions, and connecting with investors, wholesalers, lenders, contractors, and property owners.while I am just on step 2 of the journey, I am looking toward step 3 to stabilize, and not worry about if house prices drop mid project or not (or not worry as much) So to be fair this is more about obtaining and growing a real estate business not simply buying rentals for cashflow.

Defense contractors gobbling up hundreds of billions of dollars in federal contracts while making civilian aircraft that falls off the skies, because they want to cut corners and squeeze every penny they can out of production?

Is in there, but a great thing you can do now is get your "core 4" figured out - agent/lender/manager/contractor - obviously you can adjust this and do one of the pieces yourself (self-manage for example) or don't need a contractor if you do only turnkey etc but getting this nailed down early is key

and have solid contractors lined up.