What is the best way to safely and completely erase all data from old laptops?
I have a couple of old laptops lying around and want to throw them away, but have been cautious to do so because of privacy concerns of data still on the hard drives. What is the best way to wipe them? Or should I take them out and physically destroy them?
True, but if all the data was encrypted, then the drive formatted it would require physically dismantling an HDD in a clean room to recover data, for SSDs the wear leveling makes it hard to fully erase anything, but again, after encrypting and formatting the cost of the tools needed to get the data back are well above the potential benefit (i.e. there are easier ways to get people's personal info)
It absolutely is. The thing that isn't enough is doing a full disk TRIM, but I haven't seen that recommended. A single pass of dd if=/dev/zero is plenty adequate.