The question of how Santa Claus manages to visit every home in the world in a single night has long baffled children of all ages. To answer the question we must look to the other conditions of his visit. Specifically the idea that you must go to bed before Santa will come.
Santa's visit goes unseen year after year. Searches for his Arctic toy factory have similarly been unfruitful. Not because it's not there, but because it can't be seen. You see, Santa exists in a quantum state.
Subatomic particles exist not as a point but as a probability cloud. Observation of the particle causes the probability waveform to collapse and it's position to be set. Working along similar lines, come the early morning of December 25 Santa exists in millions if not billions of homes simultaneously. If he were seen his waveform would collapse and he'd exist in only one house. Obviously he'd never meet his schedule if that happened regularly. He must exist in all those places to get the job done. Children must be in bed and asleep so they won't risk seeing Santa before he can manifest in their house.