3-4 hours, usually its about 5-6 because I'll just get caught up in feeling OKAY sober and not bored so I won't smoke. But yeah, I can make a joint last me all day long because I'll split it up and pack small bowls. From the small bowls I'll take 2 hits or so and then leave the rest for 3-4 hours later when I take a few more. I like to be HIGH all day long, not STONED. =)