"Waheguru Ji Ka Khalsa Waheguru Ji Ke Fateh"

Please correct your question. It should not be as how many hours one should recite, as ritual reciting is not acceptable. One should read, understand and apply Gurbani in his/her personal life.

So question should be
How many hours one utilises fruitfully to recite Gurbani correctly, understand its meaning properly and analyses in his mind as how to apply Gurbani in his/her personal life.