Robert is an Apple lover, right down to his precious airbuds, and his iProducts.

Make sure you are looking apples to apples. 

It might be Apple stock, fine, how well can they predict the future of stock prices and risks?

I received $Y in annual cash flowTo make it apples-to-apples, the $X needs to be consistent -- how much did I sink into the investment in total? 

I plan to read both of them as I have already purchased them both but unsure which one to read first.First - The book on Rental Property InvestingSecond - The book on Flipping Houses.Now I know I can't expect to compare apples to oranges but does one book have more "general" or "common" or "basic" learning material than other?

I would open up a separate personal checking account and run all your rental transactions through that account.Do the same with a credit card.Open up a online storage such as dropbox, google drive or apple drive and save your business receipts there.

We've been trying to get Apple to accept it for the past week(s), but the process is very tedious.That said, unfortunately we had to remove links to the podcast and BiggerPockets Blog, as Apple no longer allows links to other websites from apps.  

Again, talk to your bank.Secured and unsecured loc are apples and oranges.  

That is a skill that you as the owner will need to develop otherwise you will try to get bids from contractors and be comparing apples and oranges.

So, even though it's all technically San Antonio, it's really not always apples to apples to look at long term appreciation potential for the city as a whole.Good rule of thumb - if you want appreciation, aim for areas in demand that have a finite amount of land available and you should do well.