You may need to set aside 15 to 20 minutes of fidgeting time when you get your Xbox One on November 22. Chief Platform Architect Marc Whitten told IGN. Microsoft expects the day one update to take around that long to download for most users.
Day one updates are becoming part and parcel of game launches, let alone consoles, so 20 minutes or so seems reasonable - even if it might frustrate some. Of course, others will be to care.