It surprises me how few do though. I do. Six months or more in fact. I'm in a relatively well-paid job (senior-developer-come-local-database-export) as of course are many of the people around me, in fact some should be much better off, but there are those among them who get edgy if a mistake makes our pay late by a day because they have bills payments going out soon - they have little or no cushion or emergency fund.

The grads I can understand: they are young, they have debts from student lives that they are paying off, and even if those factors are not true/significant they aren't paid as well (they will be, we promote them fairly quickly if they show the relevant aptitude & attitude, but not yet) and they've not been working as long so haven't had the same chance to build up an emergency fund.

But people who have been working for years and have partners who have decently paid jobs too? I doubt they are paying much into a pension either. In a couple of decades they are going to have a nasty "surprise"...

Of course non of this would make a monthly paycheck or two being completely delayed a worrying experience. Even people successfully following the standard 3-month+ advice would be feeling insecure at that point.