Programmers have traditionally kept their code lines under 80 characters due to old computer display constraints, but modern displays can easily handle much wider lines. The benefits of shorter lines include easier readability, ability to fit two files side by side, and easier embedding of code. However, this can also lead to awkward line breaks, especially in languages like Java or .NET with long identifier names. Many developers now prefer a 120-character limit, depending on their display size and development environment. Ultimately, the line length limit is a guideline that should be tailored to each team’s needs to balance aesthetics with functionality.
https://richarddingwall.name/2008/05/31/is-the-80-character-line-limit-still-relevant/