It's really varaible based on habits and your biology I guess. I used to drink pretty much consistently Pepsi and Coffee every day for maybe 4 or 5 years. When

It's really varaible based on habits and your biology I guess. I used to drink pretty much consistently Pepsi and Coffee every day for maybe 4 or 5 years. When I decided to give up caffeine it was like a week and a half long flu, horrible headaches and tired aches all over my body. I ended up having to take time off because I just couldn't function at work. In my case I was giving up caffeine to help regulate sleeping patterns, though I was experiencing some of the heart palpitations too.