Caffeine sensitivity and metabolism is highly, highly individualized, and it's affected by medications, etc. Its a much better idea to learn your own body toler

Caffeine sensitivity and metabolism is highly, highly individualized, and it's affected by medications, etc. Its a much better idea to learn your own body tolerance/limits than rely on a generic app. It will vary. You might also have many other reasons to limit caffeine besides being able to sleep at night - heart issues or migraines for example. An app can't take these sorts of things into account. Caffeine pretty much doesn't effect me, so I will have a cup of coffee and go right to bed if I want to. I also can be a regular consumer for weeks-to-months and stop suddenly and have none of the terrible withdrawal symptoms people always talk about.