shall / will

For the ordinary future, use will with every person: I will wait. We will wait. They will wait. Shall began as obligation, and will began as wanting. Both became future markers. The school rule that I and we take shall for the ordinary future is old-fashioned. Shall is still standard in two places: an offer or suggestion in a question (Shall I lock the gate? Shall we start?), and a duty in legal prose (The tenant shall pay the fee.). Do not use I shall or we shall as the default future.