It helps to decide what counts as an unexpected expense before you need to use emergency savings.
Think about a few costs that would disrupt your household, such as an urgent repair or a temporary loss of income. Write examples alongside the regular bills you already plan for. Use recent expenses as a starting point for estimating what a realistic setback could cost.
Record how you would access the money and how you would rebuild it after using it. Revisit the list when the household changes. The CFPB guide below explains how to frame a savings goal around your own circumstances.
Further reading: CFPB guide to building an emergency fund.