Some people use the numbers to increase their own fitness level. I constantly strive for higher speeds. But usually on rides I do by myself 1-3 times a weeks. Currently I am breezing along at a great pace of 23-25 MPH . I can't do this on the family bike rides, I go by the old rule of thumb. A fleet of ships is no faster than the slowest ship. So I will usually gear way down so I am still getting a little workout.