Note that this doesn't actually work in all situations. I have a non-24 hour circadian rhythm and severe insomnia and for a long time I could only sleep on the

Note that this doesn't actually work in all situations. I have a non-24 hour circadian rhythm and severe insomnia and for a long time I could only sleep on the shifting schedule, even with very little sleep for as long as I could manage (a couple of weeks or so). After a while figuring out which of various medications and practices seem to help (although my overall health is still not improving so it might just be an unknown health issue improving my sleep) I've been able to at least stop shifting around the clock, can usually get to sleep in an hour or so going to bed at about the same time as the day before, and now getting less sleep does seem to have some impact on my ability to get to sleep the next night. Not everyone with circadian issues has this and possibly people without might. That being said, it is a good technique when it works. Waking up at the same time every day seems to be more important than going to sleep at the same time and is both an indication of how well your sleep is doing and can be helpful in improving sleep.