One of the big benefits in AutoCAD MEP is the ability to check for interferences in your drawings. What is an interference? It's any place where one objects interferes with another, such as two ducts occupying the same physical space. If problems like this are not found before the drawings are submitted for construction, costly change orders will certainly follow. As you can see in the video below, checking for conflicts is easy. You can check for two main types of conflicts; "hard" and "soft". A hard conflict is where two physical objects such as a duct and pipe occupy the same space. A soft conflict is where an object crosses through areas like service clearances. Duct, equipment and piping might be able to installed without problems but this doesn't guarantee it'll be able to be serviced later. What good is an air handler if you can't get the filters changed? Another costly change order will be headed your way if you make this mistake. Checking for "soft" interferences helps head off these problems before they ever materialize, ultimately saving you time, and more importantly money.