How do reasoning, subtasks and tools affect usage?

Scope the task, then observe your readings

1. Official guidance lists model, task location, complexity, context, reasoning, speed and tools as usage factors. Long tasks can use much more than short requests.
2. State goals, constraints and acceptance criteria clearly. Break complex work into reviewable stages to reduce repeated exploration. This is workflow advice, without a guaranteed saving.
3. Delegated subtasks still perform model work. Do not assume subtasks or tools are free, or convert a percentage into a fixed number of tasks.
4. Compare readings within the same reset cycle, noting reading times and possible delays. Do not compare consumption across resets.