It is never enough to meditate! Actually, the meditative state is the one that supports the other three states, so it is always there. But because we are not aware of it, we call meditation when we formally seat down, close our eyes, etc. This of course is important. The ultimate goal is to be aware of the meditative state even while moving about and with open eyes. In the Siva Sutras one sutra states “the bliss of the world is the bliss of samadhi”. In other words, seeing or experiencing the bliss of the Self in the middle of worldly activities.
As far as seating down and meditating, in the beginning it is said that one should try to limit it to whatever time the body can take. In contrast to what people think who don’t seat in meditation, it actually uses considerable energy and one needs proper nourishment (maybe because certain parts of the brain get activated which need extra nourishment?).