Everybody is sleeping on 2036 for NTP. That's when the fun begins.

Assuming correct implementation of the NTP spec and adherence to the "eras" functions, NTP should be resistant to this failure in 2036.

The problem being so many micro-controllers, non-interfaceable or cheaply designed computers/devices/machines might not follow the standards and therefore be susceptible although your iPhone, Laptop and Fridge should all be fine.