Some prefer to physically destroy the drive by drilling holes through it. Or other creative means.
Most people that want to give the drive away do a DoD 5200.28-STD disk wipe exactly like the one in DBAN (Deriks boot and nuke) DoD actually stands for Department of Defense the series of numbers after the DoD is one of thier policies I believe and it has an algorithm to write random data over every sector of the drive.
Using the DoD wipe with a 3 time pass is typically good enough for the average person.
If my memory serves me correctly:
The U.S. Military does 7 passes.
The Department of Defense does 9+ passes.
From what I've read about the actual wipe the more passes the better of course and its very unlikely anything will be recovered since the data is overwritten soo many times with a random algorithm. The theory behind being being able to recover the data comes from being able to reverse the algorithm which is nearly impossible in this case. You would need a super computer probably several of them and its just not worth the time and effort to extract your information.
The algorithm is apparently a true random algorithm and not a pseudo-random algorithm. If you want to know the difference you can check out wikipedia or google.
"Sure is for people with nothing on the line.....you and me? We just get on with it."
It depends on a number of factors:
1) How sensitive is the information?
2) How much time (and other resources) can you reasonably expect a malicious individual to expend in getting the data?
3) How motivated would a malicious individual be to get the data?
A number of Governments publically release their destruction standards.
Off the top of my head I can state that in the majority of circumstances the Canadian Gov't requires triple overwrite for mildly sensitive information. To find specifics check RCMP and CSE websites.
For the majority of home users DBAN is more than sufficient.
I'm a compulsive post editor, you might wanna wait until my post has been online for 5-10 mins before quoting it as it will likely change.
I know I seem harsh in some of my replies. SORRY! But if you're doing something illegal or posting something that seems to be obvious BS I'm going to call you on it.
A third party security audit is the IT equivalent of a colonoscopy. It's long, intrusive, very uncomfortable, and when it's done, you'll have seen things you really didn't want to see, and you'll never forget that you've had one.