No, you don't have to reinstall Windows each time you switch motherboards.
No, you don't have to reinstall Windows each time you switch motherboards.
It varies based on the license you obtained: With an OEM license you cannot use it on another machine unless it's the same motherboard, otherwise it's limited to one device at a time. If you have a retail license, you can reinstall anytime you wish. OEM means one-time retail use—allowing multiple devices as long as they're activated together. EDIT: For OEM licenses, there are solutions if you upgrade your board; contact MS for a new code or run inactivated mode, which may affect performance but won't block functionality.
I understand. You're wondering if the same issue applies to your plan to install Windows on a USB using WindowsToUSB.
It doesn't function properly. You can run Windows on a USB drive, but transferring it between computers isn't possible. Once Windows starts, it detects different hardware and may either crash or boot into safe mode. Success depends on the hardware being very similar. Outcomes are usually inconsistent. If you're facing issues, I'd recommend waiting until everything is assembled. For NAS projects, consider freenas.
License matters, but the real problem is drivers. Windows 10 is meant to handle drivers better than earlier versions, though I've heard cases where it still has problems. Uninstalling all drivers won't fix it if the OS itself has issues. You can always check how it works and reinstall if needed.