Sheepdog Tip of the Day, Before Combat tip 312

Caffeine can keep you awake, but only if you are not habituated. On a normal day, four cups of coffee should be the maximum. But switch to decaf after lunch. The half life of caffeine in the human body is five hours. Two cups of coffee with dinner at 5pm are the same as one "nightcap" cup of coffee at 10pm. Even if you can sleep with caffeine, it won't be the deep sleep cycle you need.