The biggest is that Real Estate Investing is always passive. 

@Bridget Grant for one, your biggest and absolute mistake was not having a title company run title on it.

Time is your friend and it goes by faster than you expect.Personally, in my 15 years of investing, my biggest mistake with rental property is that I sold.

I think your biggest barrier is finding an asset that will meet DSCR requirements in your target location without having 40-50% down.

Brad is one of the biggest players there, broker, investor, restaurateur. 

The due on sale clause will be the biggest worry, even though it's uncommon for banks to enforce it, they have the opportunity to at any time.

Here are the five biggest companies that have made the decision to move from California to Texas, according to the latest Forbes Fortune 500.- Chevron- Tesla- Oracle- CBRE- HP

Cut free of your "golden handcuffs" with the minimal interest rates on these properties and sell them all (or the biggest headache properties) and do a 1031 exchange into a bigger property or package of multi families where the cash flow is better, numbers make sense, and you can streamline property maintenance and management rather than having 6 different single family homes. 

Working with them is the biggest mistake of my real estate journey.

Even if it's the biggest unit, you need to move into that one to satisfy the mortgage if it's liveable and then figure out how to get the tenants out.Who was your agent on this because they have not prepared you for anything?