Rent to sales ratio: Restaurant QSR a factor of 6 to 7% is usually strong,8 to 10 is average, above 10% you get into more of a danger zone because after food and labor cost (fl keys) there is generally not much profit being made.

“Slowing home price appreciation early this year in many of the most popular flipping markets put some investors in danger of flying too close to the sun,” said Daren Blomquist, vice president at RealtyTrac.

I got the distinct impression that the lenders or their attorneys realized while searching the title chain that someone had screwed up and they legally didn't have the right to foreclose.

The danger you have is that if the city ever bans short term rentals, then you will likely be losing money since you won't be able to get long term tenants in it at the price you need.

Not only was I a single female in danger every time I pulled up the the house, but I had no one to help me with this project.Then, I met an investor who actually grew up on the very block who had about 30 properties in the area.

If all owners (meaning all heirs, if the assessed owner died) sign quitclaim deeds and all lienholders either release their redemption rights are have failed to redeem during the period of one year after you send them certified mail return receipt request notice, then there are no more redemption rights and you are not in danger of losing the property."

It seems to me that old wiring with the fabric insulation poses more of a danger than knob and tube.

In no way am I an economist, or would ever claim to understand the true depth in being able to speak on these subjects, however I would estimate given the current economic climate that investing with appreciation as your primary source of growth would be a dangerous investment.Perhaps this is a showcase of my own lack of experience, but I would rather invest in safer cash flowing assets until we see the economic correction everyone has been preaching about. 

I can think of a couple on situations that should not be grandfathered, like a vent pipe open to the home interior or dangerous wiring. 

There are tons of dangerous proposals.