To answer your question about how much in tax relief you will see, it depends on your tax rate, how well the study is done and if it is engineering-based, land versus building assessed value, and so much more.

The purchase price versus land value 2.

My down payment will not be drastically different even if I put down 20% of the purchase price ($20,000 versus $18,000).

I would love to be able to maximize my investment by Building 2-3 more apartment buildings on the property, i’m just unsure of the cost of a new build versus acquiring another existing apartment building in another location.    

Debt to equity ratio… looking at overall indebtedness versus how much equity you have in your portfolio. 

I am not sure whether it is inexperience or laziness (perhaps a little of both) but I see too many investors simply take the word of another investor or seller versus developing their own "Buy Box", conducting their own estimates, and only buying if the deal fits within their box. 

I use bots to scrape county websites for bonafide leads versus services like PropStream which are less reliable.  

Similar to the lock on your door and security system in your house; the goal is not to prevent the hack but make it less enticing to attack you versus someone else.

Without knowing all of the details, I always lean toward rent versus sell, especially in southern California! 

I didn't want to get into the weeds, but you're right that it comes down to numbers, and long term hold versus cash flow strategy.