Congratulations putting up such an extensive list of good practices for typography, Wojciech Zieliński. While these guidelines are indeed important to take under consideration, we shouldn’t reduce typography to just that. For example:
- A higher x-height can also make copy more legible, because you won’t be distracted as much by the contrast between upper and lowercase. It really depends on the context of use.
- You can’t always control the width of a paragraph, in particular in UI design. Instead of forcing a character limit, you can also play with line height to improve readability. Once again, it depends on the context of the copy.
- A wider letterform isn’t necessarily more legible. In fact, quite a lot of black and fat font styles are way less legible than their narrower counterparts.
Guideline are just guidelines: they’re not set in stone, and we should always question them with a pinch of salt. Nonetheless, pretty solid article 👏