In X4 i always started with a new save but that should not be obligatory.Speaking of wiping saves, do I need to start my X4 save over to enjoy the new content in the X4 DLC? I suspect I would for any story mode stuff, but could I visit Sol and see Terran ships with the "Cradle Of Humanity" DLC from my current game save?
I enjoy new starts there as I tend to make X4 a spreadsheet simulator in the end taking over the whole game economy with own stations and transportation
Edit: And DLCs tend to add new start points telling the story from a different perspective.