Why not break the numbers down more granularly to like 25% 50% 70% 90% 95% 99% ?<p>Understanding where your users are on the curve is probably more interesting than a single number. Worrying about that last 1% really only makes a meaningful difference if your user base is huge enough that fixing something for 1% of your users can jump revenue by a significant multiple.<p>Mentally, I try and think of the 80 or 90% of users with a similar experience, needs, etc. and make it better for them. In this case, speed is good for everybody, but I care very little about the needs of that last 1% if your customers are all paying the same. No sense in putting the needs of a small number of users in front of the needs of a much larger set of users.