From the Windows 8 retail (upgrade) EULA:
"Can I transfer the software to another computer or user?
You may transfer the software to another computer that belongs to you..."
This remains the same for the Windows 8.1 upgrade EULA.
On upgrading a Windows 7 PC, this changed the terms of the original OEM EULA which was not transferable, and lasted for the lifetime of that PC only to a lifetime license on any replacement hardware.
For this fact alone, the £14.99 Windows 8 upgrade was a bargain.
Will the Windows 10 EULA be similarly generous in terms of transferability, does any one know?
I have read in many places that with Windows 10, reinstalls on the same device will be allowed - which puts the situation back to the original OEM situation where the OS is tied to the device it was installed upon only.