Maybe for older Windows versions like XP, but 7 and up are pretty good about switching hardware. I have done it a fair number of times, and only time I remember having issues was when the computer was totally incompatible with that version of windows(older Opteron without needed CPU instruction).
I always try to run Sysprep with OOBE and generalize checked before switching machines. I also check that the new machine is booting the same as type as the old(UEFI vs BIOS boot), and this is for older machines that the SATA controller is in the same mode(AHCI vs IDE).
I also expect the windows is deactivated, and that I have to install drivers for the new machine.
But with these precautions, I have not really had any issues.