Still True or Outdated?

When the shift is optional, one question decides it: is the information still true? If she said "I work at Google" and she still does, "She said she works at Google" is natural and clear. The past form, "She said she worked at Google," can hint that she left. But when the situation has changed, the shift does useful work: "He said he was coming" clearly places it in the past. So keep the original tense for facts and ongoing situations, and shift back for outdated ones.