Depends on the bowl. I can do 2-3 vortex's a day or about 3-5 standard mya bowls daily. I get home from work at about 5:00pm and smoke till 10:30pm Mon-Fri and on weekends I smoke for about 6-7 hours, so you do the math... I smoke a lot.
Although I'm not a chain smoker. I'll take a hit ever couple of minutes.