Case-in-point: Two months ago, I carefully reviewed the data sheet from which this image was taken and made engineering decisions based upon it. Today, I received another copy of the data sheet. Even though it looks the same, has the data changed?
Neither the first or second data sheets are dated, so I can't tell if the manufacturer has published revised information unless I do a line-by-line comparison. And if I am going to do that, I might as well look at the competitor's information.