Quote - Call it a day when you're stuck, but for heavens sake, DON'T delete
the PZ3!

Ditto that!  I have a WIP folder where I keep all the projects I'm currently working on and the ones that I abandoned.  There have been many times when I've gone back months (or even a year or more) later and salvaged certain ones that just didn't work out at the time.  Either I was finally able to do something I didn't know how to do before, or I simply got the inspiration to finish it up or use it as a base to take things in an entirely new direction. 

One other thing I always do is keep a detailed list (a notepad file) of everything I use for each image/project, and stick it in the relevant folder with the image and PZ3.  I find that extremely useful for those times when you look back at something you made months or years ago, realize you want to re-use a certain morph, texture, prop, etc., but can't remember what it was!

"You don't know what we can see
Why don't you tell your dreams to me
Fantasy will set you free." - Steppenwolf