When I decided to go on a new road, I figured I needed to start fresh. One channel had all of my old stuff and didn't really line up with what I wanted to do. Another channel is just for me to privately watch my stuff.
Then I decided to take YouTube seriously, so I opened up a third channel in order to make serious content and build up a crowd.
Right now, the focus is on gaming. Long term, I am planning on shifting towards Arduino and soldering projects. The name I choose for the channel was deliberate (Johnny Nongamer) since that can cater to anything. So, I don't need to set up a new channel, I just need to make a new playlist.
And that would be my advice...add new content, but make full use of your playlists.