Just like any physical object, drawings do tend to get untidy over time, and usually they accumulate a lot of redundant objects, such as zero-length geometries, DGN linetypes, and unused named objects that not only bloat the file size, but also start creating errors in the drawing.
There are many inbuilt tools in AutoCAD that help you keep drawings clean, and even when your drawings seem to show errors, these tools can fix those errors too. In this section, we will talk about four such tools: PURGE, OVERKILL, AUDIT, and RECOVER.