Author Malcolm Gladwell wrote in his book Outliers that in order to get good at anything you have to dedicate on average about 10,000 hours of practice. Miyamoto Musashi, however, advocated 10,000 days. From my point of view it takes about a million repetitions or so to completely master any movement. Those who study sword talk about doing bouts of 1,000 suburi and they are probably at right around a million if you calculate it out over a 10 year period by today's practice standard. In olden times a million would take about 3 years.
You actually don't have to do it a million times, but it takes about that many repetitions for all our baggage to fall away. We bring so many preconceived notions, ideas and "knowledge" to the activity that it makes it hard to master. Only when we "let it go" can we find what we are looking for. En route to a million our baggage becomes to heavy to carry and in order to achieve a million we have to let it go. Then, somewhere around a million we notice that we have and that the movement has become more pure or fluid. So sometimes it's not that you got better, but that all the obstacles to mastery have fallen away.
The sign pictured above is in the men's dressing room. The most poignant statement reads, "One hour of practice is one hour closer to your enlightenment." Sensei most likely put it up because as he puts it, "There's no time left." If we are to get to a million with any endeavor we need to start now because as Sensei also put it, "There is no time left to waste!"