Either we adjust or we are self selected in the first place. Maybe both.

Taking many short flights for work practically forced me to learn to sleep sitting up even during the day if I was not fully rested. Many of my colleagues and frequently flying friends can do it too. But some people seem unable to do it. I found that once I understood I could do it, there was no further practice needed. Like riding a bicycle that half your friends always fall off.

In the past year I have slept in approximately 200 different beds. About once a month I do wake up in the middle of the night with the feeling that something is very wrong. Sometimes I don't understand why there is no wall next to the bed, or why there is a window there. This feeling is acutely unpleasant, even alarming. But it goes away and I go back to sleep. It doesn't seem to drag my sleep quality down.

As a consultant in a big 4, I travelled 250+ days last year.

And I always slept like a baby. In flights, in hotels etc.,

I spent the past month travelling, sleeping someplace new almost every night. Did not get used to it. I had maybe 4 hours of sleep per night. Still, I was awake during the day and I had more functional hours to use for exploring, so it didn't bother me. Last night sleeping in my own bed was the first time in a very long time that I've had a full 8, but I don't notice any cognitive difference.