Some lessons are only learned the hard way, as these bosses found out after making a critical mistake. Backing up your creations, whether it be writing, data, or video files, is crucial. It's an easy thing to overlook: you think to yourself, “Oh, I'll back it up later.” But the first time you accidentally lose four days of work on your video edit, or find yourself staring at a blank Word document that used to be 15 pages long, you realize just how important it is to have redundancies. Suddenly,…