For how long should we sit in meditation?

The length of meditation is dictated by need. For instance, if you can sink into deep meditation within a few minutes, then perhaps you only need to meditate for a short while. If it takes longer to attain a satisfactory depth in meditation, then sit for a longer period. There is no need to make attempts to go into a state of deep absorption or Samadhi. Let it happen naturally and avoid force. On some days you may achieve greater depth in meditation than others.

The only strict guidance regarding how long to meditate is that it should not exceed one hour in duration. Meditating for too long creates mental pressure. If you have the time and inclination to meditate a second time, however, please do so, provided that you give a gap of at least fifteen minutes in between. There is no restriction
on how many times a day you can meditate, as long as you do not neglect your duties.

Ultimately, our lifestyle becomes meditative. No matter what activity we are engaged in, we remain meditative and centered within. The act of meditation triggers an ongoing meditative state, which supports all our activities.