Is doing 10 min meditation 6 times same as doing 1 hour meditation? Or is doing 30 mins 4 times same as 2 hour meditation ?
Shoot for the hour. It takes the mind about 25–30 minutes to really settle. It’s a lot like impurities settling out of a glass of water. Just being on the cushion and not allowing your mind to kick up other detritus by doing willful activity allows it to move into a deeper state of calm. You almost don’t even have to do any “concentration” work those first 30 minutes. It happens almost on its own.
After that first 30 minutes, you’re going to find that it’s much easier to follow whatever meditation object you’ve selected. Your thoughts race less and the object is more stable. You are also going to feel much, much better at the end of the session.
But! 90 minutes is really the sweet spot. In Zen temples, they used to meditate for the time it takes two incense sticks to burn down - about 45 minutes a piece. I think the Tibetans have a similar time standard. After an hour, provided that you’ve sat straight through without moving, piti (a kind of energy current that can sometimes be exhilarating) starts to arise. Depending on the level of your practice, your body might start shaking, you might feel like you want to jump up off the cushion, or, if you’re advanced, you can surf that current, relax into it, and let it dissolve into incredible bliss.
Doesn’t 90 minutes sound great? Do 90 once you’re able to. But start with 60. Long unbroken sitting is always better than short intermittent sits.
Ultimately the goal is to be lucid, clear thinking, relaxed, calm all the time, any posture, any activity. So the question you ask, those differences are relatively minor and irrelevant to the main goal. Only if your goal is to attain certain deep samādhi states is contiuous single long session of relevance.
I have bought a new heavy duty motor pump, I use that in fields to pull water from earth.
During initial days, it needs to be settled properly so using for few minutes or so at regular or irregular intervals might damage the motor. It needs to be run properly under controlled voltage and for ample time.
Similarly, adhittahana ripes and more likeliness arise if meditation is done for long time instead of few minutes.
If during initial days, motor is given excess load by using for longer time then it might damage itself badly, same way for meditation if done by a newbee might do damage instead of good.
After enough time and once it's settled, motor can be used for small durations.. similar way meditation can be done for short intervals depending upon the spare time one gets or it can be done while doing some work too.
But as it's heard that meditation is more than this materialistic motor as once a meditator ripes, it can be done for days too.
So choose time wisely, can start with 30 minutes to 1 hour to few hours and then according to need, will, time from few minutes to days.
Meditating one minute per day at the same time of day every day for 30 days is much more powerful than meditating 30 minutes on one day only.