If punch cards were 160 columns wide, we'd all be enforcing that as the maximum line width. It's arbitrary. I typically go with 'about 1/3 of my screen width'

If punch cards were 160 columns wide, we'd all be enforcing that as the maximum line width. It's arbitrary. I typically go with 'about 1/3 of my screen width' so I can develop in multiple windows without horizontally scrolling. That's a lot more than 80 chars on a 4k screen.