I have a pet peeve: opening a drawing from someone else and finding that the layers are inaccurate, or even worse, nonexistent! I use the SelectSimilar command in AutoCAD to help me repair such issues. This tip is also handy for checking your own work, or projects you are overseeing, to correct instances of objects on misplaced layers.
Type SelectSimilar in the Command line, then type SE for this command’s settings. In the SelectSimilar Settings box, you can choose from a variety of options to help you get objects on their correct layers (but you obviously would not want to use the Layer field). For example, say all the blue text on the drawing belongs on layer TEXT_BLUE. In the Settings box, select Color and Name and click OK. Then select one of the blue texts and hit enter. In the Properties box, you will notice the Layer is *VARIES*. This confirms that not all of the blue text is on the same layer. Simply change the layer from the drop-down menu to TEXT_BLUE. In cases of nonexistent layers, you may need to create some layers first before performing the SelectSimilar command.
Notes from Cadalyst tip reviewer R.K. McSwain: This is another good use of the SelectSimilar command. Just be sure to verify the Settings inside of the SelectSimilar command so you'll know what the command is actually selecting.