Destroy is permanent. The guest, its disk, and the assignment of that
instance are torn down. Hourly charges stop once the server is no longer in
the billing population.
A short gap (under 24 hours) between destroy and a new deploy does not reset
loyalty tenure. Longer gaps do.
If you only need the server off for a bit, stop it instead. A stopped
server still bills by the hour because the capacity stays reserved.