I quit cold turkey and consumed around 1200mg/day, not by drinking energy drinks but coffee, 6 strong cups of filter or more. I made sure to also quit caffeinated sort drinks and switched to herbal tea.

The immediate withdrawal symptoms started after around 24h and consisted of headache, cold sweats and brain fog that lasted around three days and seriously impeded my ability to work. However, the psychological craving just... never really got better once it plateaued. I always felt a bit more understimulated than before I stopped, and a bit less motivated.

I kept it up for about 1.5 years or so before I decided it wasn't worth it. The first cup of coffee seriously gave me euphoria comparable to a low dose of amphetamine. That was so pleasurable that I tried to keep my consumption to one cup per week, but even with that spacing I felt the tolerance build up again.