Assuming, for discussion's sake, three hours of practice in a given day, I'd recommend the following distribution:
75 min technical exercises and studies
35 min new repertoire
35 min in-progress repertoire
10 min chamber music
15 min performance-ready repertoire
10 min sight-reading
If you have five hours to practice, it might look more like this:
75 min technical exercises and studies
60 min new repertoire
90 min in-progress repertoire
30 min chamber music
30 min performance-ready repertoire
15 min sight-reading
I'll refer to the 3-hour scenario for this next breakdown. Looking at a 75-minute chunk of time, and knowing it has to be filled with technical activities and studies is a great launch. But further reduction can help a lot. Let's say you are currently working on the following specific technical activities and warm-ups: tone, arpeggio, tremolo, ascending and descending slurs, LH independence, i-m velocity, scales and a couple of Sor studies. So, you're left with something like this (links go to prior posts describing the activity in detail):
5 min tone
10 min arpeggio -Giuliani (or arpeggio -Carlevaro)
10 min tremolo
5 min ascending slurs
5 min descending slurs
5 min LH independence
10 min i-m velocity
15 min scales
10 min studies (5 min each for two)
It is challenging to stop playing something like an arpeggio exercise after ten minutes; it could easily be done for 30 minutes. One needs discipline to switch gears on a schedule like this. But the long-term payoff is significant. (I should note that in the formative stages, I encourage students to immerse deeply in each technical activity, doing the particular arpeggio routine for, say 30-40 minutes each day for a few weeks, until it is well-established and the hands are doing it correctly and consistently. This immersion comes at the expense of other activities which are temporarily put on hold. Then, dipping into the exercise for ten minutes each day effectively reminds the hands about the technique, offers opportunity for improvement, and warms up the muscles.)
Sor Variation 6
The dilemma most students fall into is that the challenge of learning new music can lead to the abandonment of repertoire already prepared. There's a great slapstick scene in the film "The Gods Must Be Crazy" in which the lead character is trying to pick up a pile of gourds. He can hold several, but each time he bends down to add another, two fall out of his grip. He keeps trying and trying, each time, picking up some and dropping others. It's hilarious. We need to find a way to add pieces to our existing pile without dropping the ones we're already carrying. The best way, in my view, is to keep playing them. That's why I include on the list above "performance-ready repertoire." It doesn't stay performance-ready if it is abandoned for weeks or months at a time. Ideally, playing through the pieces you already know how to play (once!) should be your reward for a day's work on newer material. You can play them, alternately, from day to day, at full concert tempo and intensity, or slowly, or quietly, or with a metronome, or any of a number of other ways, each of which will add to your confidence and security with those pieces. And in doing so, prevent them from falling out of your grip, and landing back in the pile of "in-progress" pieces.
Time-distribution plans like those above, are necessary default frameworks for daily work on the instrument. They can't be rigid, though. When a new piece or study is introduced, it is fine for it to take more of the day's time than such a plan would normally provide for. But after the initial immersion phase passes, and the piece enters the repertoire as an "in-progress" work, the time distribution settles back to normal, allowing more time for exercises, chamber music pieces, sight-reading, etc. The same is true for performance preparation. In the days immediately before a performance, it is natural to favor the piece or pieces featured in the performance, and allow the time allotted to the remaining activities to be reduced.
There are other elements of time management we need to consider. Do we practice all in one session or spread out our work, throughout the day? In my experience it has always been better to set up several sessions each day. Ideally, you would begin the day with a 1.5-2 hours of technical work, interspersed with some other items from your list. This type of start guarantees that you'll go through your whole day feeling like a "player," and that later, when you get another chance to practice, you'll already be warmed-up. A second session, sometime in the afternoon, is the perfect time to address the most difficult new challenges you face, whether fingering new scores, memorizing, or overcoming special difficulties in your pieces. A third session, maybe later in the evening, is a good time to do some sight-reading and run through your concert-ready works, as well as reviewing the day's accomplishments and new material. Not every day will offer blocks of time like this, so you have to adjust how you manage the material each day. We are constantly barraged by distractions and opportunities to do other things. Determining when to stay focussed on the guitar and then doing so is one of the signal challenges we face.
Another time-related question, is simply, how much should we practice? The simplest answer is: more! But there are shades of grey. It is better to put the instrument in the case if you are too fatigued or distracted to accomplish anything of value. Sometimes other things need to take precedence. We need to know how to prioritize. One of the easiest things a teacher can say is "practice more!" But really, the better advice is to practice better. I find I can generally accomplish more in ten minutes than most of my students seem to accomplish in a day's work. This is so because I know exactly what I need to do, and can give the specific item a laser-like focus. We need to constantly look for ways to make our practicing more effective, more efficient, more productive. The better we get at practicing, the less of it we will need.
(See also Practicing I: What To Do In The Practice Room and Practicing III: Hints and Tips)