Hi
Technically using an Unlicensed windows 10 is violating Microsoft Service Agreement. But you can use Windows 10 as long as you want without activating it. The only problem that you'll encounter is there are limitations in using unlicensed windows 10.
Unactivated Windows will only download critical updates; many optional updates and some downloads, services, and apps from Microsoft (that normally are included with activated Windows) also will be blocked. You’ll also get some nag screens at various places in the OS.
In short: The core of Windows will work without activation, but some desirable non-basic elements, services, and add-ons, will be absent or limited. And if computer is unable to download all needed updates on the machine, chances are you're computer will be vulnerable to malware attacks and data corruption or loss of files on worst case scenario.
You can find additional details on the link below:
https://windowsreport.com/windows-10-used-witho...
Note: This is a non-Microsoft website. The page appears to be providing accurate, safe information. Watch out for ads on the site that may advertise products frequently classified as a PUP (Potentially Unwanted Products). Thoroughly research any product advertised on the site before you decide to download and install it.
Hope this information helps, have a good day.
Thanks,
Orlando Q.