IT is usually the last group told, and the first thing noticed if it's wrong.
Moves get planned around the lease, the furniture, and the construction schedule. Technology is looped in once those dates are already fixed - and only then does anyone discover that an internet circuit can take weeks or months to install, that porting a main phone number requires its own notice period, and that badge access and network login need to be ready on the same morning, not sequentially.
None of this is exotic. It's simply late, because the longest lead-time item is usually the last one ordered rather than the first.
Office-move IT setup treats the move as a sequencing decision worked backward from the confirmed occupancy date: identify what has the longest lead time, order it first, and align everything else against that constraint rather than the moving truck's schedule.