~9 is my magic # too. Your partner may delude themselves into feeling "fine", but I'd guess it's more that they feel no different than the last time they did i

~9 is my magic # too. Your partner may delude themselves into feeling "fine", but I'd guess it's more that they feel no different than the last time they did it. It's not even a conscious thing necessarily (although I have met people who proclaim, just a little too loudly, they only need <X hours of sleep in some sort of weird macho "ironman" flex). It's possible; there are a VERY FEW people on the earth who need way less sleep/night than normal, but like multitasking it's a super small % and the number people who think they are in that % but aren't is massive. Like the number of people (in the US, at least), who think they're in the "better than average" set of drivers.