I plan on giving away old computers : to protect my personal data, is it enough to remove the hard drives?

I have a desktop from ~2009 and a laptop from 2014 (Samsung NP700Z7C) that I’d like to give away so people can reuse parts if they wish to.
However, I don’t want to take any risks regarding personal data (both were my personal PCs, with al… Continue reading I plan on giving away old computers : to protect my personal data, is it enough to remove the hard drives?