I eat lots of meat, dairy and eggs so I don't think I have any issues with niacin. I eat tuna fish at least once a week and red meat once or twice. I have dairy every day in the form of milk or yogurt or cheese.
It's actually not difficult to get our needed daily niacin. Even coffee has niacin so those who have the habit of drinking coffee in the morning are getting a nice amount of niacin. What happens sometimes though is that we may have conditions that prevent our body from absorbing the niacin in foods. But a blood test will show any deficiencies easily and the doctor can prescribe supplements in that case.