How much cash reserve?

[Chingju Hu]

Hi BP!

As a solo person buying rental properties (and not a big real estate corporation), I'm wondering how much cash reserve do you typically do for each property??

I like to have cushion in life, and for own living expenses, I always keep at least a full year's expense in my bank so I know I'll be fine no matter the economy, next recession or whatever happens in the world.

And when I'm buying a property, naturally I need some cash reserve for the property, in case, God forbid, something goes wrong. Currently I'd like to keep at least 6 months of expense of the property in bank so that I know i'll be fine for at least 6 months. How do you think, is it too much or too little? 

Are there any formula to calculate the cash reserve?