But I'm having a harder time figuring out what some good macro indicators are for real estate investors. 

Could someone inform me the formula to figure out the average for a rehab for a flooded home?

For example, I purchased a list from List Source a few months back and at least 30% of the mailers were returned.I'm sure someone has a way around this or a way to improve their rate of returned mail but I don't want to spend the money to figure out how to optimize someone else's list. 

For example, I purchased a list from List Source a few months back and at least 30% of the mailers were returned.I'm sure someone has a way around this or a way to improve their rate of returned mail but I don't want to spend the money to figure out how to optimize someone else's list.

@Stephen Shelton,You haven't figured out your "why?"

I have this question here as I am trying to figure out how to go about this top:What are the 3 most efficient ways to collect rent? 

The first thing I think you may want to do is figure out exactly what areas you plan to target so that you could work to become very familiar with those areas.

With the live in flip I would figure it would make more since after the house hack because you could stop paying rent free up some capital to do renovations and shorten your time to flip to enjoy renovation and refinance and so on.

Figure the value of a home/apartment/etc?

This method does not increase cash flow it buys cash flow at a cost of approximately $2 for every additional $1 based on the opportunity value of cash.