Allah says in the Quran: It is Allah that takes the souls (of men) at death; and those that die not (He takes) during their sleep: those on whom He has passed the decree of death, He keeps back (from returning to life), but the rest He sends (to their bodies) for a term appointed. Verily in this are Signs for those who reflect." Quran, Chapter 39 verse 42
This means: every time you sleep, Allah takes your souls, amongst many other souls he takes during sleeping. Then Allah decides who is going to be given another chance. For those who are blessed with another chance, Allah will permit their souls to go back to their bodies, the rest he keeps back from returning to life i.e. they die.
This means: each time you go to bed you should never be sure you will get up again, you ONLY have 50% chance for coming back to life.
This means: each time you go to bed you should be prepared for your hereafter. This means: when you wake up the next day you should appreciate how lucky (blessed) you are. And say "Blessed be the one who returned my soul to my body, and granted me another chance". This is what Rasulullah SAW used to say when he woke up.
This means: when you wake up the next day you should make sure you utilize the new day as much as you can before sleep time comes, in case the new day you are living is the last chance you are given.
This means: you should try to make sure you recite Surah AL-MULK (chapter 67) before sleeping, because Rasulullah SAW promised that one who reads this Surah before sleeping is saved from the punishment of the grave.
Allah Knows best
May Allah forgive us all and bless us with a happy life in this dunya and the hereafter. Ameen