Basic rental finance question

[Rich Cavanagh]

I'm new to the game and have been purchasing and renting out properties slowly over the past few years. "They" say the first 5 properties are the hardest!

Anyways, I have 2 properties under my belt and I'm saving for the 3rd. I need to focus and pool my savings as much as I can for future down payments on more properties but I play it very safe and like to have money on the side for each property I own for emergencies(vacancies, broken AC/Roof/ repair etc ).

Not to mention I am in FL with the threat of hurricanes.

Whats a good rule of thumb you guys use for gauging the size of your rental emergency funds?