I have defined an enum, with a static property which loads a unit from user defaults. My question is how is this static property initialized? When a user changes defaults within my app, this property is not updated until restart.

enum Length: String, Some Protocols {
     //...some stuff
     static let preferredUnit: UnitLength = UserDefaults.standard.getUnit(forKey: .preferredUnitLength) 
} 

When I make this static constant a computed property, it’s still not updated when a user changes their preferred unit despite updating defaults on unit change.

enum Length: String, Some Protocols {
     //...some stuff
     var preferredUnit: UnitLength { UserDefaults.standard.getUnit(forKey: .preferredUnitLength) }
} 

I leverage this static constant like so:

var someProperty: Measurement<UnitVolume> {
     return value.converted(to: Volume.preferredUnit)
}

The new unit is only loaded on app restart. I am okay with this, but would like to understand why.