For example, we replace marginal roofs, rip out all the old galvanized plumbing because it saves me a lot over the long run.

Plus the added requirements around getting drawings and general contractor for even adding a tiny closet.

He deals with vendors and contractors.  

If you're willing to be more active, purchase a property or two in an area you personally know well and have key contacts (handypeople, contractor, lender, etc.).

please send me a case example I'd love to read. that's one appraisal. the knowledge I have as a licensed general contractor working with investors from 5 cities at a time all over the country buidling 3 different floorplans I would say trumps one ADU you read about online 

My main account has all the rents deposited and all expenses deducted such as mortgages, some utilities and an electronic payment app connected to the account to pay contractors.

A complete overhaul of the kitchen and bathrooms, including cabinets, countertops, LVP flooring, electrical and plumbing fixtures.

Other risks, the contractor walking off the job, a storm hitting and delaying the project for weeks, someone breaking into the home and stealing stuff (which happened just the other day to a client of mine), a squatter, or drunk driver driving into the house (happened a lot at my old job as a firefighter lol).

Also, the ability to find good deals with an accurate budget to complete the project up front from some good project managers/general contractors.

Once you decide on a contractor I would keep the fire marshall in the loop as to the scope of work and the timeframe for completion.