I've had migraines for 10 years. I would guess about 1 per week/fortnight on average, lasting for 8ish hours. Never drank coffee until this year, when I started drinking it along with a high dose of aspirin (~1000mg) when I felt a migraine coming on. Almost a complete cure for me, much better than the medicine my doctor prescribed for me. So, for anyone else reading, like everything with migraines, your mileage may vary.