We also had units on the 2nd floor right above a busy sidewalk and didn't want them falling down on people's heads. 

One roof, one sidewalk or parking area to maintain, one tax bill, all maintenance in one location, etc. 

Bonus depreciation is just a special part of the US tax code.It allows you to take accelerated depreciation on portions of your property depending on when an asset is put into service.At the time of this writing, you can write off a huge portion (60% in 2024) of many qualified components that have a useful lifespan of 15 years or less.That means a certain percentage of things like landscaping, sidewalks, latches, appliances, fences, certain flooring, etc is depreciable in year 1.The bonus depreciation rate percentage changes yearly depending on the administration and the tax code.For years 2015 through 2017 first-year depreciation for all the items on a 15-year schedule or less was set to 50%.It was scheduled to go down to 40% in 2018 and 30% in 2019 and then 0% in 2020.But then Trump got elected, and he enacted the Tax Cuts and Jobs Act.That moved the bonus depreciation percentage to 100% from 2017 to 2022.In 2023 it went down to 80% and it’s currently at 60%.Depending on who gets elected again, 100% may be back on the table.Only time will tell.We know that the US government wants to incentivize more development and ownership of RE.They want Americans to continue to build and maintain our physical world.That’s why real estate is one of the most tax-advantaged assets in the US.Depreciation and bonus depreciation for RE are very positive and will likely continue in the years ahead.

They are a combination of roof pitch, dormer count and sizes , covered porch square footage, attached garage, 16 inch eaves, 2x6 construction, driveway with sidewalk leading to front door and more.

I'm watching a sidewalk being built in my neighborhood and in order to continue it all the way down the street the city would have to go more than 10 feet into some of these properties because of trees.

First, unless you have a good bit of experience and have done this before, I doubt you'd hit $60/sf if you had to put in utilities, separate meters, sidewalks and other common things you'll find with multi-family development. 

By 10 pm I had 300 boxes to check on the sidewalk.

Class D   Bars on every corner  , houses with bars on windows  , cars on blocks and stripped ,  drug dealers on the corner , drug addicts  sleeping on the sidewalk , tents on the sidewalk , gunshots , ladies of the evening ( and day ) , abandoned  houses  , graphity on buildings .   

I dug 6 inches below the sidewalk grade, trucked out about 30 1-yard trucks of soil, packed in 4 inches of concrete base and 2 to 3 inches of gold-colored rocks.

What if the sewer lines go, and the sidewalk needs to be torn up with a back hoe?