Everyone is a little different, I'm on the shorter side of things, I start coming down after 3-4 hours, some people stay up as long as 10-12 hours, really just depends on you. Just remember, water is your best friend with meth, if you think you've had enough water, you probably haven't, meth dehydrates you at an extremely high rate, and trust me, dealing with dehydration after a binge sucks.