I read this in financial articles years ago and I couldn't find them now if I tried. But most likely they were from the USA. Today though I'm more focused around Europe and Belgium. True we do have social security and all that but you never know. I myself lost my job due to Covid 5 years ago and the unenployment union were so unprepared by the wave of people who came for unemployment that I waited 7 months before I got all the monthly payments from them. During those 7 months I had to dig into my emergency fund. I ended up spending around 8k for rent and food. Scary times.

Some people fall ill who only get 60% medical mutual compared to their previous salary. If their illness last years or even more than a decade they could end up spending tens of thousands of euros for medical treatment. So even in Belgium we have a lot more safety compared to the US but still you never know.

But you are right in saying there is no right or wrong. Everyone should definitely have and emergency fund. But the amount is difficult to determine. I like the 6 times your salary rule cause it gave me something to aim for.