“Clearances are usually valid for five years, and they go with the individual.”
That policy is insane. If that’s so, why 5 years? Why not 10 or for life?
The length of time is dictated by how frequently a periodic re-investigation must be accomplished. If the clearance was for 10 years, they would only have to be investigated once every 10 years, instead of once every 5 years.