Understanding cash on cash

[John McCormack]

Can someone please clarify for me how calculating CoC return is helpful particularly when using the BRRRR strategy.

I'm reading how it is really only a calculation for the first year only??

During the first year of the BRRRR there may possibly be 3-ish months before renters are in. Wouldn't this skew calculations? Or do you use "potential" 12 month income in order to calculate "potential" CoC?

We tend to be buy and hold cash flow investors, so would calculating cash flow after renovation be the best method for determining a good deal?