Yes, DME arcs are good. I like to have to think while i'm flying, it keeps me awake!
You will find when you start flying professionally (it will happen - eventually!) that you are frequently expected to fly aircraft with varying degrees of unserviceabilities. Also, things do fail in flight. Thats what the MEL is for, to provide guidance as to whether you can accept an unserviceability or not.
You will also find that the aircraft you fly in any sim is the worst, most unserviceable aircraft in history. So many failures, each time you get airborne!
TTR