What changes?
A typeface must support the language, symbols, and sizes the product uses. Test real paragraphs, numbers, and labels rather than judging only a large sample word.
Use it in your work
Check English and Russian text, including punctuation and small interface labels.
A common mistake
Selecting a display font for every paragraph because the title looks good.
Context matters
No font is universally readable; size, spacing, and rendering also matter.