https://www.reddit.com/r/typewriters/comments/1q54adl/how_long_does_an_electronic_typewriters_ribbon/

https://new.reddit.com/r/typewriters/comments/1f29hxm/how_many_pages_on_average_does_a_nylon_ink_ribbon/

How long will a typewriter ribbon last?

Can it be calculated? <br /> How many letters per spool at 16 yards?

Examples over time like https://new.reddit.com/r/typewriters/comments/rx9rmd/les_stewart_has_the_record_for_typing_1_to_1m_it/