I typically recycle my computers to an old buddy that fixes them up and gives them to folks who need them. I do not want him to have to buy a new drive.
I have felt comfortable using 'boot and nuke' for years.
Darik's Boot And Nuke | Hard Drive Disk Wipe and Data Clearing
For
me personally I feel I can raise the cost of recovery beyond the value of any asset I have on the disk so the probability of anyone getting anything is almost zero. It is much more likely I lose that asset in some other way, i.e., a robbery, ineptness of someone who also has information about me for on line banking, bill paying, etc.
I boot and nuke the drive (I forget the exact options). It does take some time to make several passes.