We really can't tell you anything based on the information offered, it depends on local laws, costs, rents, materials, permits, etc.....

They haven't been a maintenance issue other than the glass shades once getting broken which I was able to replace with used shades from a used construction material store like Habitat for Humanity.

Am I being irrational to have him strip sand and retain?  

Cheapest paid pln would be $120 + Tax.SRFax ($36 a year) or MetroFax ($80)are better bet as you would be able to retain your fax number.

For affordable housing, the average construction cost is generally lower than market-rate projects but still substantial due to various factors such as labor, materials, and compliance with affordable housing regulations.Affordable Housing Construction Cost: The cost to build affordable housing in Oregon ranges between $250 and $350 per square foot as of 2024.

Would the recurring payments be if I charged a fixed rate retainer for my services each month instead of a % of monthly revenue? 

The first quote I got was $1,200 - mind you the materials are about $100 - and it's easy to do - could do it myself but have other projects where I'm focused.  

Cost savings over 30 years is irrelevant as it's unlikely to materialize. - No one knows what will happen in the future.

I'm thinking 7 years + to trade equity, 12-15 years for material wealth generation. 

Construction materials: Frame, no basement, roof: asphalt shingles, Floor: Carpet on stairs and bedrooms, LVP: Kitchen and living room.