)
As a result of exile and the dispersal of communities, different locales developed somewhat different versions of the prayerbook (e.g., Edot HaMizraĥ, Ashkenaz, Sephard). The core prayers vary only slightly, yet there are larger divergencies within the material added in the medieval and early modern periods. The rule of thumb is that each person should continue praying the way his or her ancestors did, thus deepening the connection to Jewish tradition.
However, those who are accustomed to use a particular version, and would find it difficult to change to the version of their ancestors, may continue to pray the way in which they are accustomed. Converts may choose whichever version they wish. Generally, they adopt the custom of the community through which they grew closer to Judaism. A future Sanhedrin may create a unified version, which will include the best parts of each tradition. Even then, there would still be room for each community to have different emphases and different melodies.
