Even what counts as a "month" depends on a lot of things. You could go by months' worth of current expenses, but I think what really matters is how many months you could actually live on the money, which depends on how variable your living expenses are (which is a mix of "real" constraints and psychological constraints on how frugal you could get if you needed to).
Exactly, my current monthly expenses are higher because I have a job. If I suddenly became jobless then my variable cost budget would change accordingly.
It does help though to take the general rule of thumb of 3-6 months or the other one I've heard is 1 month expenses for every 10k in salary you expect to make and put that away. If something bad ever does happen it's good to know you can tighten up and stretch that out even more.
