Been wonderin this for a while but haven't known how to word the question right. (And probably still will be confusing, but here goes...) Is there any difference in the way "Empty trash..." and "Secure empty trash" work? I always just use Secure because if I delete it, I don't have the software to get it back again and Secure empty trash makes me feel like it's being deleted all of the way-- thus, I feel like I'm getting more hard drive space back. Is that just a mis-conception?
Secure empty trash writes over the data to truly erase it. ...But you aren't getting any more free space that way - you're just ensuring that your data cannot be recovered.
...but to be clear, you shouldn't get "more hard drive space back" using Secure Empty Trash, it just makes it more difficult, if not impossible, to recover the deleted files. As an FYI, you can also erase free space with Disk Utility if you don't want to Secure Empty Trash all the time, or if you want to make sure to wipe out everything you've deleted. Edit: hmm. a late edit above... great minds, I suppose.