It’s detachable in my fridge.
I use the egg holder on the door shelf for small bottles that would otherwise fall over when the door is opened. Medicine or nail polish, that sort of thing.
I also the egg holder to … hold the eggs … after they’re boiled, so I can fill the egg cooker instead of boiling just a few at a time. I use cold boiled eggs for sandwiches or salats.
I do not use it for holding raw eggs as those already come in an egg shaped carton.
About a week maximum.
The taste changes over time, so I prefer using them in 1-2 days.