I have drank approximately 11,000 gallons of milk in my lifetime. When I was riding my bicycle approximately 300 miles a week I used to average around a gallon a day. I was a member of a racing team that was sponsored by the dairy farmers in our state. More typically I have drank approximately a gallon every two days.
I switched to non-fat about 30 years ago. Although I have never noticed any negative side effects that I would attribute to excessive consumption of milk, I have had concerns that too much milk might be bad for me. So I have tried various substitutes over the years but have never really enjoyed any of them.