I think you know my thoughts already from my articles,
The Fine Art of Practice, which I thought I'd mention for all the new folk.
In a nutshell, I would do one of two things:
Cover all four areas (see my article), allowing 15 minutes each ... so that you are done in an hour, then do it all again with your next hour of practice, but new material obviously.
or
Cover all four areas, allowing 30 minutes for each.
Either way, you'll get 30 minutes of each ... which will give you a good rounded amount of practice time ... and you'll see the most productivity ... in my opinion.
Whatever you do, even if you feel devoting 30 minutes for warm-up stuff (for example) and want to shorten that, make out a schedule for you to adhere to. If you just wing it each day, you may find yourself wasting precious time, playing things you can already play, and not working on the things you need to work on.
Some disciplined individuals have good results making a schedule of what they will practice on a daily basis. This allows them to address problem areas as the occur.
For me, planning and writing out a schedule well in advance helps me set good goals. Without goals, it's hard to have a clear vision for what we are trying to achieve specifically.
If you can get two hours a day in ... you'll be slammin' bro! You can get a LOT done in that amount of time.
