Depreciation on a Rental Property

[Nicholas Norris]

Hey Guys!

So i was using an excel spreadsheet to analyze a property that I may purchase this Fall. However, I noticed there was a cell labeled "depreciation" which always comes out as a loss. I tried to research what this was, and I came across a few posts. However, my mind is really not registering what depreciation is and how it affects my end of year profits. I know it has something to do with tax write offs, but I was hoping someone could elaborate on what depreciation is and how it will affect my single family rental. 

My main questions are:

1. Why is depreciation a loss that eats at my profits?

2. Is depreciation on a property required?

Thanks!