Plenty repeatedly expound on the need for a LLC none have evidence to support the need of any protection beyond having adequate insurance coverage.Nothing beyond boogey man scenarios.I do believe it is a mistake either inside or outside of a LLC to pay down a income property mortgage however conservative investors will continue to place themselves at very high risk by parking their cash in real estate.

The creator of the 401k recently said it was a big mistake to create the 401k and he wishes he hadn't done so.2) I can buy a house with less that 20% down but then I have roofs, AC Units, tenants, toilets etc.

Don't get me wrong I love fixing mistakes of other people; however, my biggest issue is when a "professional" doesn't do what they are supposed to be doing and should know better. 

If you are a newbie, then that can avoid a lot of expensive mistakes. 

OP refused to fix their mistake and told the tenant they had to pay for it.

This is the biggest mistake with newer investors, buying on pro forma.Please be patient and buy only on actuals.  

This would be a major mistake for the seller assuming that my contingency is accurate.

- Regret: Help others not make the same mistake. - Pearl of Wisdom: Pass along your best concise advise!

Appraisal was done through the lender so maybe that was my first mistake.

This means there is plenty of buffer in case mistakes happen and it also means the person borrowing the money has significant skin in the game as well.