Do I drink coffee? Well I used to, but I had to stop becuase I had a period of 4 weeks in which I didn't fall asleep and now I'm restricting my caffeine intake (By having none) this also is influenced by the time where I kept getting intestinal cramps and vomiting when I ingested caffiene...
The frequency I had it at was 2-5 cups a day (I also drank about a litre of Pepsi Max aswell while often having 1-3 cans of Relentless (High caffiene content, 32mg per 100ml and comes in cans that are 500ml))
No 4 a day isn't too mental, but depending on how long you spend between getting up and going to work that 3 you have could be something worrying. My dad has like 5-6 cups of coffee a day (It's all he drinks unless he is in a raid, where he has Pepsi because it's quicker to get)
Don't worry about the amount you drink, the time you know you have too much is obvious (You start having trouble sleeping or such)