How much money should we have at home in case of a disaster or a war? Experts shall specify circumstantial amounts

More and more questions arise in public space about how much cash is worth at home “just in case”. In the age of close-up payments and net banking, many of us do not carry money in physical form. However, experts inform — in situations of crisis, network failure, blackout or armed conflict, access to electronic means can be restricted for respective days. How much cash should we have at home to guarantee financial security?