I think @Photosymphysis and @Kazzyhoward make important points from the 'busy/organised/coping' end of the spectrum.
And I think it is a spectrum -- I'm probably towards that end of things in that I have a FT job, a young child, a husband who travels a lot for work, I write novels on the side, live in a big, very run-down old house I'm project managing the renovation of while we live here, an active social life, look after elderly parents, and have had a lot of challenging life stuff (frequent house moves, a country move, health issues including two surgeries) in the past 18 months.
However, compared to a close friend, who deals with all this and two children with SN, I'm definitely middle-of-the-road.
But there are also people who are simply very low-energy.
I have a friend who is a healthy, married man in his mid-40s. We used to do exactly the same job with the same responsibilities in the same workplace, yet what I could easily accomplish during normal office hours working three days in the office and two at home around my son, took him six days a week because he was so disorganised -- he almost always went in one day of the weekend! He would show up in my office regularly on an ordinary working day making this kind of 'panting and exhausted face', as if he'd just endured some major trial of strength. Doing a work project with him was awful, because he seldom did things on time or accurately and would show up unprepared for public-facing stuff.
Doing anything with his children exhausted him, and something as simple as having their friends over for a (rare) playdate, or taking them swimming or to buy school shoes would knock him for six for a week. If you asked him how his week was looking on Monday, he would pull a face that suggested he was facing major surgery and say he had to go to his son's parent-teaching evening on Thursday night. He didn't maintain a single friendship.
His comfort zone was so small, everything sent him into a tailspin.
I realise he's an extreme example, but he's someone whose struggle with the basics I saw up close.