I'm putting this up because, of course, I want to respond to what she is saying. First of all, we should have profound respect for anyone who teaches at Curtis, probably the foremost training school for orchestral musicians in the United States. But, you know, I have a little teaching and playing experience myself!
In one sense I completely agree with her and, in fact, that has been my practice in recent years. I only practice about an hour a day. Though when I was preparing for a recording session in October, for a couple of months before I was practicing between an hour and a half and two hours a day. But back when I was a student I typically practiced anywhere from three to six hours a day. An hour and a half of technique, an hour on learning new repertoire, an hour on maintaining old repertoire and another hour on new repertoire. That was my ideal when I was a concertizing soloist. I could simply not have gotten done what I needed to on an hour a day, even a very focussed hour.
For example, on one occasion I had to learn the Villa-Lobos Guitar Concerto in three months for a concert with the CBC Vancouver Orchestra. I wasn't immediately sure it was possible, so I asked the producer to give me a couple of days to look it over. In a weekend I memorized the first movement. Believe me, you can't do that in an hour a day practicing. I probably spent a couple of hours the first day just working out the fingering.
Then there is the story of Arthur Rubinstein who apparently learned, from memory, the Grieg Piano Concerto in one massive eight hour session (I think I read this in his autobiography). Or Mstislav Rostropovich who memorized the whole of Shostakovich's first Cello Concerto in four days! That took a lot of hours.
So while I entirely understand what she is saying, I think that I would disagree with some of it. You should not limit yourself to one hour a day and, honestly, I kind of doubt that she has never practiced more than an hour a day.
But I wholeheartedly agree with her comments about focussed, concentrated, mindful practicing. Practicing without full awareness and concentration is worse than not practicing at all. I saw a clip where Isaac Stern was talking about practicing and he was saying that you have to practice in exactly the right way. It can take several hours to correct the bad habits you might have picked up in one hour of practicing the wrong way!
She is also dead right about spending most of your time working on just those things you have difficulty with.
Hmm, what would be a good envoi for today? I used to go out with a bassoonist who trained at Curtis and she told me that her teacher had her learn a different Vivaldi bassoon concerto every week. Which, I strongly suspect, took more than an hour a day. Here is the Concertus Hungarieus, under conductor Valeri Polyansky with Valeri Popov on bassoon.