On average how many hours per month would a realist digital painter practice

[Kozuka]

On average how many hours per month would a realist digital painter practice on a regular basis

[Lightpunk]

I'm not sure this is really answerable. Do u mean a beginner, or a professional etc? If you are starting out my advice would be to just practice/paint as much as you can to whatever you can consistently and regularly do within your current schedule and goals. Small consistent amounts regularly are better than bursts of effort and long gaps.

[cfhd]

I think that as long as you are drawing at least once every single day then you are bound to see some sort of improvement. Obviously the more you draw each day will speed up the improvement. Even if you were a professional then I would assume that you would still need to draw pretty much daily in order to keep your skill level high and keep improving.

[Hitsu//San]

8 to 12 hours per day, maybe less if you're already a professional

[dpaint]

Even as a pro I make sure I get in at least 8 hours a day, thats for any media though not just digital, but Hitsu is right more if you can. When I'm busy I do at least 16.