Why do translations need to be revised, and about how long does a good translation last before it needs to be substantially revised?
Translator A: The first published translation of Science and Health with Key to the Scriptures into another language is usually a rough cut. But it’s also the best it can be at the time. It heals and it serves to open thought—it changes the chemistry of thought in the country where it is being read. As this translation is studied, the Field grows. The mentality of that Field enlarges in terms of its ability to understand metaphysical ideas. A generation or so later, the same people can see how to improve the translation, because their spiritual awareness has increased.
Translator B: The first time a work by Mary Baker Eddy is translated into another language, there may be a limited number of capable native translators. But as more translators emerge, and as the original translators learn more, the need for a revision becomes clear. Timing for this may vary widely, as growth in spiritual understanding varies. It also depends on the growth of Christian Science in a given Field.