Some people dedicate a lot of time throught their day for meditation. It is a part of their every day life. There is no one who can tell you how much time you shuld dedicate to meditation other than yourself. meditation as well is not something you just are done with in a week for many. after 14 years i still meditate every day. The more you mediate, the better you understand what it is and how often or lenthy you should make it.
Divinechaos in right. It doesn't matter how long you meditate, it is your body, and you have control over it. However, while meditating before performing a particular spell, there is a minimum of how long you should meditate. (Be it five minutes to ten)