A small RE Investment mistake can cost you a lot of money and ruin future chances of success.

Pipes burst in the walls and flooring can be ruined.

I hear the sound of the Atlantic surf on the Portuguese beaches can soothe even the blackest, most maggot-eaten ruin of a soul. 

It would seem that if you're always in the red, that at some point, you could get yourself into a lot trouble with the bank or potentially ruin your credit.  

None have ever doubled in any time frame, ever.The point I would like to make to all young investors or those that are doing this FOR A LIVING is DO NOT RELY ON APPRECIATION when making investing decisions.That's exactly what millions of so called "investors" did in the mid 2000's and with rare exception they lost their investments to foreclosure or short sale, ruined their credit, and caused the worst recession since the Great Depression.

It ruins their relationship with contractors.

The seller may not be OK with letting you "handle" the mortgage, because you could go in default and ruin his credit.

However since most of these are significantly older properties, one bad experience is all it takes to ruin it for someone starting out.

I complained to FTC, CFTC, and BBB so they sent it to Universal credit to ruin my credit. 

Ruined the plumbing, holes in walls, smoking inside, completely annihilated the floors, etc.