I'm a beginner that has been playing for about 4 months. I typically practice for 4-8 hours a day WITH focus(this is with several breaks from 5-30mins).
I was just wondering, would it be better to split my practice into two times per day and repeat some of the things in the latter part of the day that may be able to improve such as technique drills?
I practice 3-4 hours per day, and take a 5-10 minute break every 45 minutes or so if those 3 hours are all in one session. This gives me a chance to digest the new material, rest my hands, get a drink of water, etc. I think the maximum amount of time one can truly focus and learn is about 45 minutes, and taking a brief rest will help rejuvenate me a bit.

I usually split the sessions into an hour in the morning, 1.5 hours in the afternoon, and 2 hours or so at night.
As with most things in life, growth happens during downtime. You can't build muscle unless you get a good workout in and then REST and get plenty of SLEEP! I am a thorough believer in the positive effects of downtime. I would recommend practicing in the morning, then letting it go all day and then practicing again at night. That gives your brain and fingers plenty of time to process and reconfigure during the day, and then again overnight.

If you think about it, this principle is why it is highly recommended that you practice at least a little bit every day instead of big long practices sparingly. The guy who plays 10 minutes a day will make so much more progress than the guy who practices for 5 hours once a week. 5 hours straight with no downtime will not get you nearly as much progress as several practice sessions with downtime in between.
Last edited by Sample246 at Jan 7, 2017,
As long as you don't exhaust yourself mentally or physically then play as long as you like. These days I can very very rarely play for more than 2 hours. After an hour or two at most i feel both mentally and physically exhausted so I call it a day and wait for tomorrow. I agree with the above in saying that growth happens during downtime. I know if I push myself too hard and keep going I will not properly digest the material I've been playing.
Personally I wouldn't recommend playing for more than 2 hours a session, but it differs for everyone. If I was dead set on making progress as fast as I could then I would play 2 hours in the morning and 2 hours at night. Everyone is different though.
Basically, don't force improvement. It will happen naturally.