Why new windows?

Newer windows, roof, kitchens, bathrooms, HVAC etc.

Who was responsible for having a retaining wall to keep the earth from sliding?

Apparently I just missed a small window to argue my tax bill for another 8 months. 

But, if you use this spreadsheet to determine how much things cost, I'm curious where you'll find windows for $0

Since 1931 this house has only know open doors and window units.

Start making low offers with 3 day windows.  

You said you live in Austin, no better way to learn than directly so, there is a syndication group Viking Capital LLC, that is buying/raising for a 252 unit property in NewBraunfels, about 45 min south of Austin, watch their webinar at their website below and they have an 82 pg slide show as well, then take a 3 hour trip to go see it, walk the property, go into office ask about the units available/leasing how the market is from the office staff, look around for quality of property/deferred maintenace needed then drive the area for other competitor properties.

At some point you need a new roof, plumbing, windows, HVAC, etc - setting aside 5% of rent may cover a new water heater, but very few components of a house last more than 50 years.It's 2024: books written in 2015 or 2018 are based on the market conditions in year 5 years before they were written.

Hard lessons:-unexpected things will happen at the worst time. starting a vacation in the BVIs and you get that dreaded tenant call. the window fell out or there is a heat issue.