*Three main condition that define a שינת קבע vs a שינת עראי:*
1) you change into pajamas 🥼
2) you go into bed 🛏️
3) you sleep at least 30 minutes 🕡
-If your missing any of these, its a שינת עראי (temporary nap) 💤 🤏 UNLESS this is your only option to sleep the night, like on an airplane ✈️
-If you take a שינת קבע (set sleep), after the sun sets, you have demonstrated that your day is halachically over and when you wake up need new bracha