General rule of thumb that works for me: the number of characters should roughly match the number of handwritten characters that fit onto a normal letter page.

General rule of thumb that works for me: the number of characters should roughly match the number of handwritten characters that fit onto a normal letter page. For me, that is between 50 and 70 characters. This also roughly matches the number of letters in the standard manuscript format [0] used by the publishing industry for literary works. [0] https://en.wikipedia.org/wiki/Standard_manuscript_format https://en.wikipedia.org/wiki/Standard_manuscript_format