In formal writing, the future tense requires shall for the first person, will for the second and third. The formula to express the speaker’s belief regarding his future action or state is I shall; I will expresses his determination or his consent. A swimmer in distress cries, “I shall drown; no one will save me!” A suicide puts it the other way, “I will drown; no one shall save me!” In relaxed speech, however, the words shall and will are seldom used precisely—our ear guides us, or fails to guide us, as the case may be, and we are quite likely to drown when we want to survive, and survive when we want to drown.
—Strunk and White, The Elements of Style, 1959 ed., pp. 45–46.