Artur Rubinstein had let his technique get sloppy. But the appearance of Vladimir Horowitz on the scene woke him up (I believe). Though a long-established world star, he decided to devote himself to practice. He had what became known as his “summer of practice."
Do we not reach points at which we need to be awakened and challenged, either to reestablish our expertise or to make new progress to a higher level of service and integrity? Any time, be it spring, summer, autumn or winter, might be our "summer of practice," that period in which we devote ourselves intensely, anew, to wholesome habits or learn new techniques or skills, or develop new tools for our work. If the challenge ceases to come from within, let God send us one from without.