user-1: I am currently meditating thirty minutes per day. I wonder whether I should meditate an hour instead or meditate for thirty minutes twice. 
Basically, I meditate on compassion and after thirty minutes I'm not generating much of anything. I just sit there moving about on my chair, wondering about the time, etc. 
Does this saturation after thirty minutes occur because I have always meditated this amount of time before? Or is it because I'm just not ready yet? In other words, are we used to whatever amount of meditation we're usually doing?
If this is so, would it be better to just always try to sit an hour if I'm capable? Should I just meditate as long as I can sit, whatever the quality may be?

user13709: Right Immersion is the eight stage of the Noble Eightfold Path. It is upheld and nurtured by the preceding seven stages of Right View, Right Thought, Right Speech, Right Action, Right Livelihood, Right Effort and Right Immersion.

AN7.45:1.1: “Mendicants, there are these seven prerequisites for immersion.  What seven? Right view, right thought, right speech, right action, right livelihood, right effort, and right mindfulness.

Circle back and deepen the seven prerequisites. Then, naturally, immersion will deepen.

user17298: Please do not enter into competing with yourself mode. Pushing yourself to sit one hour just to follow the clock does not bring much benefit to us. It is just misusing our power of will. Instead, better try to listen to your mind when 30 minutes is about to finish. What does it say? "Ah, I'm glad I'm finished!" And immediately after that: "But I should sit longer!" And the struggle starts. This might bring an important insight into how with all these shoulds and shouldn'ts we create our own suffering. Once you understood that, just relax and stay sitting as long as it is appropriate for the situation you are in. Sometimes it's 30 minutes, other times 45 or 60. But whatever are the minutes, the benefit is the same if you manage to maintain this kind of awareness of your mind's work and than manage to extend this awareness also into the rest of the day. Good luck!  

user10100: 
Should I just meditate as long as I can sit, whatever the quality may be?

If you don't have good enough teacher, YES you should because you maybe get the problem and fix them yourself when the very long long time gone by. It is definitely better than watching TV.
However, if you have good teacher, NO you shouldn't because he will teach you the proper better faster tools to modify your living for the meditation, such as yoga before meditation, or body trick for longer sitting, etc. The meditation will be faster higher qualities and longer period by this way.

user17498: If your purpose of meditation is to achieve jhana, the quality of your concentration while meditating is much more important than the length of your sitting. 
Jhana is defined in "The Path of Purification" as "The centering of consciousness and consciousness-concomitants evenly and rightly on a single object, undistracted and unscattered". 
In order to approach this state of mind, one should try to eliminate any trivial thoughts and focus on your meditation subject in a period of time. So I think you should try your best to prolong the time you focus on your meditation subject without any trivial thoughts arising. Try not to resist or indulge in your thoughts. Just put them in the "background" once you find them. During 30 minutes of meditation, you may find that you can only concentrate for 5 minutes or even less. Making this concentration-time longer should be the objective.

user2282: Joggers or long distance runners didn't just start out running for hours. They build up their stamina slowly and steadily over time. So use the same approach for meditation. Build it up gradually and don't settle for the 30-min achievement. It's probably too short for any significant deep absorption state anyway. There're advanced meditators who immerse themselves in deep absorption for days.

-1: <p>I am currently meditating thirty minutes per day. I wonder whether I should meditate an hour instead or meditate for thirty minutes twice. </p>

<p>Basically, I meditate on compassion and after thirty minutes I'm not generating much of anything. I just sit there moving about on my chair, wondering about the time, etc. </p>

<p>Does this saturation after thirty minutes occur because I have always meditated this amount of time before? Or is it because I'm just not ready yet? In other words, <strong>are we used to whatever amount of meditation we're usually doing?</strong></p>

<p>If this is so, would it be better to just always try to sit an hour if I'm capable? <strong>Should I just meditate as long as I can sit, whatever the quality may be?</strong></p>
 13709: <p>Right Immersion is the eight stage of the Noble Eightfold Path. It is upheld and nurtured by the preceding seven stages of Right View, Right Thought, Right Speech, Right Action, Right Livelihood, Right Effort and Right Immersion.</p>

<blockquote>
  <p><a href="https://suttacentral.net/an7.45/en/sujato#an7.45:1.1" rel="nofollow noreferrer">AN7.45:1.1</a>: “Mendicants, there are these seven prerequisites for immersion.  What seven? Right view, right thought, right speech, right action, right livelihood, right effort, and right mindfulness.</p>
</blockquote>

<p>Circle back and deepen the seven prerequisites. Then, naturally, immersion will deepen.</p>
 17298: <p>Please do not enter into competing with yourself mode. Pushing yourself to sit one hour just to follow the clock does not bring much benefit to us. It is just misusing our power of will. Instead, better try to listen to your mind when 30 minutes is about to finish. What does it say? "Ah, I'm glad I'm finished!" And immediately after that: "But I should sit longer!" And the struggle starts. This might bring an important insight into how with all these shoulds and shouldn'ts we create our own suffering. Once you understood that, just relax and stay sitting as long as it is appropriate for the situation you are in. Sometimes it's 30 minutes, other times 45 or 60. But whatever are the minutes, the benefit is the same if you manage to maintain this kind of awareness of your mind's work and than manage to extend this awareness also into the rest of the day. Good luck!  </p>
 10100: <blockquote>
  <p>Should I just meditate as long as I can sit, whatever the quality may be?</p>
</blockquote>

<p>If you don't have good enough teacher, YES you should because you maybe get the problem and fix them yourself when the very long long time gone by. <strong><em>It is definitely better than watching TV.</em></strong></p>

<p>However, if you have good teacher, NO you shouldn't because he will teach you the <strong><em>proper better faster</em></strong> tools to modify your living for the meditation, such as yoga before meditation, or body trick for longer sitting, etc. The meditation will be faster higher qualities and longer period by this way.</p>
 17498: <p>If your purpose of meditation is to achieve jhana, the quality of your concentration while meditating is much more important than the length of your sitting. 
Jhana is defined in "The Path of Purification" as "The centering of consciousness and consciousness-concomitants evenly and rightly on a single object, undistracted and unscattered". 
In order to approach this state of mind, one should try to eliminate any trivial thoughts and focus on your meditation subject in a period of time. So I think you should try your best to prolong the time you focus on your meditation subject without any trivial thoughts arising. Try not to resist or indulge in your thoughts. Just put them in the "background" once you find them. During 30 minutes of meditation, you may find that you can only concentrate for 5 minutes or even less. Making this concentration-time longer should be the objective.</p>
 2282: <p>Joggers or long distance runners didn't just start out running for hours. They build up their stamina slowly and steadily over time. So use the same approach for meditation. Build it up gradually and don't settle for the 30-min achievement. It's probably too short for any significant deep absorption state anyway. There're advanced meditators who immerse themselves in deep absorption for days.</p>
