One thing that you can never over do when working on projects, whether it's personal pictures/movies, animation, professional jobs or school work, is back up your work!
Personally I've heard too many horror stories and have become rather 'anal' when it comes to backing up my work/life. Typically, at the end of each day I back up using software called Back2Zip to an external hard drive that stays connected to my computer. Then after the project (depending on it's size) I burn it to DVDs, then back it up to another external drive. Both the DVDs and hard drive are stored in a fire proof safe in my basement (just to be certain that if a fire were to happen they're safe), then back them up again to the external hard drive that's connected to my computer. Yes, it may overkill, but I couldn't imagine losing all that hard work!
Another major thing a lot of people don't realize now days with all the digital pictures they capture with their digital cameras and phones, if you have all your pictures saved to your computer and something happens you could potentially lose years of pictures, movies and memories for forever. I try and back up my home pictures/movies every 2 months to DVDs then again at the end of the year (again, storing them in the fire-proof safe). I think backing up your files are so important and something that needs pure diligence when working and living in a digital world.
So remember kids, always back up your work on a daily basis, then back it up again, then store it in a safe place (if you want, back it up again). Hopefully nothing ever happens with your hard drive, computer or your house catches on fire... but if it does, wouldn't you rather be prepared and not live with regret and lose all your hard work and memories from over the years?
Here's a tale of how Pixar almost lost Toy Story 2 while they were well into production...