Practicing calligraphy mainly depends on the number of days you insist on. To put it simply, I practiced calligraphy for a summer vacation and set aside 30 minutes every day, so I can write quite beautifully when I first started school.
If you are an office worker or go to school now and don't have much time, you can train for 20 minutes every day, which is beautiful for most of a semester, that is, 3 months or 4 months.
If you are particularly busy, you can pass the exam by practicing calligraphy for at least 10 minutes every day and practicing calligraphy for one semester.
If you want to practice calligraphy and become a famous artist, you must practice hard for half your life.
Remember, writing is not fast. 30 minutes is not about how much you write, but how many words you can write. Calm, practicing calligraphy can cultivate sentiment.
I hope my answer is helpful to you.