The most important one to me is: have a specific plan, do your research, don't rush into any decision and follow your gut. 

I am deciding between a gut Reno/addition and a tear down to the basement.

The home was completely gutted.

I finally got the guts to introduce myself in the forum and I know I won't regret it.

We will do full gut rehabs but its gotta be around 5k purchase price for that.  

Learn how to say "no" and walk away from some deals and trust your gut.  

Deep in my gut i feel that there is another reason why she is in such a hurry, a part of me felt that she was wanted, or maybe someone is looking for her because she seem to be very paranoid.

@Michael S. regarding our financial analysis - we considered everything including a complete gut rehab with new plumbing and electrical, but we did not consider that it might be a total loss, or that our gut job could also involve structural repair.  

@Dana Yobst due to the age of the building it's going to be tough to find an Insurance Carrier that will do replacement cost unless the property was gutted and everything has been updated.  

@David Torres nails it... as soon as somebody walks down the hallway and sees that bathroom, they will (fine.. may*) be instantly turned off, and think in their heads they have to gut the entire thing.