Most of us have learned through painful scar tissue, to make SURE that we back up quite frequently.
I too am in the camp of manual saving, and like bitflipper, I do it both before and after any significant edit or operation in a project, as well as for any AHA moments.
I also make sure that any project where I have done a single edit in the current session, and it is open - and I step away, even just to run out for lunch, that I close the session and save the project folder to an external backup drive, so that if the hard drive should fail while I am at lunch, I still have the work saved off to somewhere I can recover it from.
I spent over 20 years in mainframe technical support, and we learned VERY early into it all to always make sure you have backups, both local and offsite, of any data that is critical, PERIOD. We actually had a case where we had a major power failure that also took out the backup power systems, and the instant heat melted down some of the mainframe's solder, and needless to say it took lots of stuff with it. Well, turns out a set of the backup tapes were physically damaged too, so we turned to our offsite backups and were able to piece things together from a week prior, and then apply all logged transactions in a forward recovery operation to get all but the data that was literally in-flight at the moment the power had gotten cut. That data would have been lost forever, were it not for redundant backups.
Save, Save, Save, Save, Save, Save, Save. It IS a mindset.
Bob Bone