Hard boiled eggs will last for up to 1 week in the refrigerator.
Always keep hard boiled eggs refrigerated if not eating them within 2 hours.
It's okay to leave hard boiled eggs out for a few hours and even for a day such as for Easter egg hunting but after Easter egg hunting you should let the kids know that they need to eat the hard boiled eggs or refrigerate them until they are gonna eat them.
Or use plastic eggs with prizes in them instead of hard boiled eggs for Easter Egg hunting.
But if you're just hard boiling eggs make sure to refrigerate them within a few hours of hard boiling them or eat them.
Hard boiled eggs do eventually go bad and when the hard boiled egg goes bad it will smell rotten and will almost take your breath away when smelling the bad hard boiled egg.