You can claim to be the best guy in the world at finding and analyzing deals, but when the market turns against you, and you just went all-in, even on the best relative opportunities that market had available at the time, there is nothing you can do to prevent losses, especially if your debt has a maturity date that will force your hand.Timing the market is an interesting concept. 

You can use bat insulation or spray foam, which has the added benefit of giving you an air-tight seal and also keeps the bugs out. 

Trump has said many times in recent days he wants to prevent evictions, but his latest executive order does not ban evictions.

It also prevents you from making the #1 noobie mistake, which is buying in the hood just because it's cheap.

But, they do get to eat a lot of pizza.Debt prevents you from becoming an investor. 

If you hire a PM, your financial account structure can be simpler.If you plan to continue purchasing rentals, I like some key accounts at the "management" level (income, opex, tax, owncp, reserve) and only have 1 checking account per property to prevent having 100 accounts and unnecessary complexity.

What prevents them from doing that?

The more rehabs you do the better understanding you will have of the market for contacting work and materials.Doing a rehab every so often prevents you from being sharp with your budget.For those with limited exposure, ask others in the industry and always run your numbers based on being overbudget and overtime. 

Where are you getting your Air BnB projected revenue?

Quote from @Matthew Crivelli: Personally, I'm not a fan of Air B & B.