"Change" is manifestation of idea. If you have the idea that sleeping 8 hours a day is beneficial, you are very likely to act like it.
Imo, ideas form within the spectrum of indoctrination and "epiphany".
Indoctrination is something that you hear over and over, and sort of taking it as granted. Parent to children, school to students, religion to devotees, government to citizen, social media to general public, hackernews to us developers, all impart their flavors to our mind and we act according to it. Take sleeping for example, sleep well, sleep long enough, sleep early shouldn't elicit much debate, we treat it as truth more of less. On the other hand, dietary cholesterol consumption, which is considered, advertised and indoctrinated as bad for more than 5 decades has now garnered some attention to consider otherwise [1][2][3]
Epiphany is circumstantial, event driven. Either you have a lightbulb moment, or reality decides to slap you in the face. Having a close friend/relative die at a young age will either makes you treasure life a lot more, or send you into deep depression. But it will change you forever for sure. On the other hand, again taking sleeping as an example, I have been a night person since teenage, habitually sleeping at 3am, 4am, feeling drowsy in the morning and study/work in the late evening. "I prefer working in silence" is the excuse I gave to the then self. One day it dawn on me that there are only 24 hours a day, if I can get things done in 1am before sleep, I can equally get things done in 6am after sleep. And if I can rest well, I can get things done quicker. No new information just one day I viscerally feel that shifting the biological clock earlier makes more.
1. https://en.wikipedia.org/wiki/Ancel_Keys
2. https://en.wikipedia.org/wiki/Seven_Countries_Study
3. https://en.wikipedia.org/wiki/Robert_Lustig