[theandrewbailey]

How long is 'a few years'? Controlled environments shouldn't be necessary for unplugged drives, just keep them at or slightly below room temperature.

I've had three external hard drives for 7 years, and none have stopped working. I have one, and keep two somewhere else (office, family). I connect one for a few hours every week/month to update, then leave alone until needed, or rotated with one elsewhere.

[Merman_Mike]

I'd want to verify the existing data and maybe add some data once a year or less.