If it detects a major hardware change or even too many minor hardware changes within a set number of days (I believe it's 180 days before it resets) then it crosses the threshold and requires reactivation.
Ọ bụrụ na ọ chọpụta mgbanwe ngwaike dị ukwuu ma ọ bụ ọbụna ọtụtụ ngwaike ngwaike na-agbanwe n'ime oge setịpụrụ (M kwenyere na ọ bụ ụbọchị 180 tupu ọ maliteghachi) mgbe ahụ ọ na-agafe ụzọ ma na-achọ mmegharịghachi.