As others mentioned can you afford the negative cash flow?

This is one of the things that @Matthew Irish-Jones mentioned above - be careful about putting #3 on his list above #1 and #2.

Some honest little birds might have mentioned a few things….

As other people mentioned the areas do change pretty quickly. 

HOWEVER; if you aren't going to use your full last name, then it's important to upload a pic to your profile (which you have) The reason being, when someone has a common name, with an initial and you are trying to @mention them, if you have a list of 5 David R's with the stock icon, it's impossible to know which is the correct one. 

I'll look up the group you mentioned.

So if your using margin at let's say 12% interest rate, to do the mentioned S&P gaining at 8% or heck let's say 10%.... congratulations you just found a neat way to go a couple hundred thousand into debt.

However, for building materials, we get 99% of them from the four mentioned!

As Peter and Jonathan mentioned relying on similar comps and/or local agent knowledge is the key here.

From what you mentioned, it might be necessary to evict them earlier in which case you need all of those issues documented.