I believe that quality of your practice time matters much more than quantity. Checking the quality of your practice session is more important than counting how many minutes did you actually practice.
There is a catch, however.
As I found out, some aspiring guitar players are so concerned with getting everything right and so worried about making mistake, that they end up paralyzed, not knowing what to do. They are obsessed with details but at the same time they are losing the big picture from the sight.
Quality doesn't really matter if you practice 5 minutes a day. You won't become a phenomenal guitar player no matter how focused your 5 minute practice session is. If you are aiming for quality, it also has to go hand in hand with decent quantity. How much you need to practice depends on your goals and aspirations.
If you are too concerned whether you are doing everything right, here's what I want you to do.
The 85% solution
I got this thought from Ramit Sethi, the founder of famous personal finance blog I will teach you to be rich. He applies this solution when he talks about getting your money under control, but it also works perfectly fine with guitar practice.
The idea is very simple, here's how it goes:
Getting started to get your guitar practice under control is more important than being perfect right from the beginning.
What we want to do is to get 85% right and just forget the rest. We don't need to obsess over every detail right now. Learning how to practice properly is a skill that you have to develop. And yes, it takes time.
If your are too concerned whether your are doing everything right, relax. No matter how hard you try, you won't be perfect. That's just the way it is. Perfectionism is a sure way to failure and frustration.
Optimizing your practice time can start with such a simple thing as getting a practice journal and planning your next practice session. (Now stop reading and go ahead and do that, you can thank me later :-))
Let's stop debating minutiae. We don't need to manage our practice time perfectly, let's take it one baby step at a time instead. (Did you get your journal already?)
It doesn't matter how much information you consume, if you don't apply what you have learned. And you haven't learned anything, until you've changed the way you practice.
Getting better results is about testing different approaches and experimenting with various practice strategies to see what works and what doesn't. It is not about reading, it's about deliberately improving the way you learn and practice.
The most important step is to practice consistently - 5 or 6 times a week. If you are not doing that, stop worrying whether you should learn A mixolydian or B harmonic minor scale first. It doesn't freaking matter. Once your practice regimen is consistent, start worrying about more advanced stuff. You have to find time for your guitar practice no matter how busy you are.
Get the important things right and don't try to be perfect. The more you learn, the more you see how imperfect you are. And that's the beauty.
And last but not least, enjoy your practice session.