Standard advice says "no caffeine after 2pm" but analyze: what's MY caffeine cutoff? Map my caffeine metabolism: based on my age, genetics, tolerance. Calculate my half-life: if I drink coffee at 2pm, how much is still active at bedtime? Show me my personal cutoff: this is when I need to stop based on my metabolism and bedtime. Give me the caffeine audit: track current intake and timing vs. sleep quality. Include: whether my cutoff is earlier or later than standard advice, how to test my sensitivity, and if caffeine is my sleep disruptor.