[alrehn]

I think most people can change their sleeping habits. If you actually practice good sleep hygene and make consistent habits around sleep and you still can't get to sleep at a reasonable time, then you are not the norm and may have a medical condition.

[epochwolf]

Good sleep hygiene, work, and having a social life aren't always compatible.

[kolinko]

Honest wuestion - what do you base this on? Anything besides personal experience?

[mannykannot]

Well, I can say for myself that the younger me adapted faster to timezone changes than I do now. That adaptation is presumably driven by the diurnal rhythms of the destination, but given that a fair amount of modern life is conducted under artificial light (and artificial darkness, for those who sleep in), it seems plausible that sleep patterns could be modified to some extent, through adjustment to the already-artificial diurnal cycle.