If you’ve got financial goals, if you want your family to be financially secure and not have to worry about being wiped out by a roll of the die, then you need an emergency fund.
For individuals with uneven income and those who want a more secure cushion, that suggestion may increase to 9 months’ worth of expenses, just in case.
Setting up an emergency fund is not something you absolutely must do overnight. Build towards a goal amount each month by budgeting a little towards the fund until it is fully funded.