These days a simple erase is almost as simple to unerase. If there is anything personal at all, there is almost no excuse to let the drive fall into another persons hands. You can do things like 3 or 7 pass secure erasure of the entire drive, then stick new stuff over the top, but for non operational equipment that is a tough chore. Easier to pull drives and destroy them physically, then send the rest off to recycle.
molṑn labe'
"I am a mortal enemy to arbitrary government and unlimited power. I am naturally very jealous for the rights and liberties of my country, and the least encroachment of those invaluable privileges is apt to make my blood boil."
--Ben Franklin