There is no limit in calligraphy. Rules in calligraphy are the starting point. Once you master them you can break them, but you cannot break something you cannot see or touch.
In his book, Outliers, pop psych writer Malcolm Gladwell said it takes approximately 10,000 hours of “deliberate practice” to achieve mastery in any field. Now this may or may not apply to every discipline, but in my opinion extended hours of practice is certainly needed in fields like art, music and sports. So, how long would it take to master roughly 16 different skills?