This is a relatively common investment strategy.

We also switch all common entry door locks to kwikset smart key pushbutton locks.

Very common when you start to do multiple flips at once.  

Is this something that is commonly required.

Recently, a common pipe within the building caused damage to a small portion of the floor.Thankfully, the building’s management company accepted responsibility and would like to move forward with repairs.

As Dave says, this is considered a 1031 exchange as Dave says trading in into and out of land and farm land is fairly common.

The thing that would concern me the most are the smoke detectors in the common areas (hallways and basement). they are supposed to be hardwired and connected. if one goes off all of them should go off. fortunately for you that is something easy to test.

Leverage is a common tool people use in the stock market to enter a position they don't have capital for.  

More commonly I see 6x yearly revenue.

Square footage is historically more common.