Sleep greed

Sleep greed is a phenomenon especially present in beginners and inexperienced polyphasic sleepers, but also (less often) in those who are more experienced or skilled and may be overconfident from a lack of failure in the recent or whole past.
It presents as the desire to want more and more when it comes to pushing their sleep, usually in the form of more reduction or more flexibility.

How to spot it

Here are some hints that a schedule switch (or consideration thereof) is sleep greed - of course, none of these are absolute and one is not enough to argue greed:

• There is very little increase in quality of life compared to the old schedule / There is no point
• A sleeper who is currently on a reducing schedule that works well for them wants to try a significantly harder schedule
• The target schedule has a TST below 5h
• Extremely high confidence despite no past successful attempts at the desired schedule
• A significant increase in the schedule's maintenance need that the situation of the person desiring to switch won't necessarily be able to provide for
• The schedule is one which is difficult to keep up socially (many sleeps, lack of forgivingness, very unusual awake time, etc)
• The desired schedule is one which is far from the default form of that schedule type (e.g. M3 with the core very late to make evening social time work, without adjusting the naps)

Consequences

Sleep greed rarely results in successful long-term adaptations - although success is obviously not impossible. However, the consequences of failure are usually quite significant: In cases where a schedule is working just fine and adaptation was successful, switching to something harder can be a quick way to undo all the work that went into what is already working just fine.

In cases where adaptation has yet to happen, it can result in an infinite back-and-forth: Start adapting something with a high chance of success; feel really confident because it is going well; greed strikes; throw away current progress and try something extremely hard; give up; repeat.

Overcoming sleep greed

If sleep greed is causing you pain, it is usually best to look for the disadvantages of the "desired" schedule and list them very consciously. Then also list all the good things about staying with the doable schedule. Consider also the prestige of having a successful long-term adaptation. It also makes sense to ask friends and other polyphasic sleepers for help overcoming your sleep greed - and if you are one to care about social pressure, you can also ask them for peer pressure.

Ultimately, there is not some way to surely stop it. Some impossible schedules are just really desirable. Sometimes, only failure will teach this, and in that case: Let yourself fail, and fail hard: Stick with it until you begin to hate the schedule. Then you will probably be able to take a break from the desire, at least for now. Unfortunately, this is a pretty radical solution and its consequences suck, so try it at your own risk - but it's better than switching back and forth forever for sure.