Leave external slim drive plugged in or unplugged?

[butyfigers]

Is it better to leave an external slim drive plugged in or unplugged if it is not in use? I've been leaving it plugged in but I'm not sure if that's the best for the circuits or things along that line.

[Billycar11]

probably not a big difference
if its used daily probably leave it in
if its used rarely unplug it