Cost planning.

Build estimates that explain their inputs. The articles here cover LLM usage accounting and the capacity required to retain logs. Both distinguish measured quantities from assumptions, make units explicit, and keep incomplete information visible so a planning result can be revised when better evidence arrives.

Use the token guide when the question starts with model requests and reported usage. Use the storage guide when it starts with event rate, record size, retention, and copies. Neither a usage total nor a raw byte estimate is a complete invoice: document the components included in your particular calculation.