In MCTB, Daniel says most of his progress was made doing sits that were less than 4 hours and most of those less than 90 minutes.  In the last few months, I've upped my frequency of sits, but not the length.  I'm sitting 1 hour in the morning, 5-10 minutes on morning and afternoon breaks and 15-20 minutes at lunch, depending on how quickly I can inhale...uh, I mean eat. ;-)  

My longest sits are still only about 75 minutes. Frankly, I get fairly physically miserable after 75 minutes, but I know the length could be increased little by little with minimal misery.  I also realize working with the discomfort I would encounter while increasing my sit time stamina might be beneficial as well.  

I work 3 12 hour shifts per week, so I have several days off and plenty of time to work on increasing the length.  I am going on a (somewhat) self directed 10 day retreat in September and think it might behoove me to be able to sit longer for retreat puropses.  So...

For those of you who sit longer than my current 60-75 minute limit, what are the benefits/good reasons you would give to increase the length of my sits?  Or is the length irrelevant in your experience?  Do the benefits for longer sits apply mostly to a retreat setting or do you find longer sits helpful on an off retreat basis?  

Thanks for your kind responses in advance! 

I love long sits. I like pushing through the discomfort and boredom. 

One benefit/good reason is to push yourself a bit (not to the point of damage of course) and work through the discomfort and pain. 
The longest sit for me has been a little over 3 hours. I usually get in two 2 hour sits a week, and 90min/75min are pretty standard. That does not say anything about how much insight I have, etc...I just have a high tolerance for discomfort and sometimes it takes me a while to settle in.

To be honest, after a while, there's not much to it for me. The pratice does get deeper for me, more equanimous, and 'after glow' lasts a lot longer. 

Lately what I've been doing is having 4-5 hour sessions. Where I practice continuously for that period of time but alternating sitting/walking. Maybe you can try that. 

All that being said, the solid advice around here is to really focus on the quality of the sit. I could be sitting for 2 hours, but not really balancing the 5 factors, etc...and that happens frequently. 75 mins is more than enough to get some good work in...

Concerning Ingram, the dude seems way too hyper for long sits haha. Love him. 

For me long sits only make sense when practice is really taking off so adding time to the clock seems like the natural thing to do. Otherwise I've found intellectually deciding to meditate more/longer is much more likely to originate in chasing/craving and turns out to be counter-productive. In those cases it would be better to put the energy into finding a good balance between doing multiple sits focused on practicing well, and finding ways to bring good practice more and more off-cushion, such as mindfulness of chores or gently observing habitual craving/aversion and so forth - or whatever makes most sense for you. Also may indicate some metta practice would be helpful.

Shinzen Young made some interesting comments about how to make faster progress in his YT videos, and one of them was that its important to regularly push your sitting duration, to increase the length of your sits. Something like twice a month to try sitting for longer than usual. I guess partially its because we can become accustomed to being able to sit a certain duration, so pushing that boundary furthers our determination and patience skills.

Personally I find that longer sits are necessary to go deeper. And they can increase your confidence too, when you realise you can sit longer than you feel you can, way past the aversion. Particularly if you sit through some strong pain which then disappears - often in my sits it seems that intense pain won't go away until the end of a sit, so being able to sit with it until it vanishes is a good benefit too that is more likely to occur on long sits.

I find long sits beneficial too because towards the end of a sit, the aversion and mind-spinning can start to rev up, impatient to leave the sit. If the sit is planned to be longer than usual, you definitely don't want to spend another thirty minutes or more spinning around in that, and so there can be a sense of "necessity" in feeling your way into having that aversion die down, or developing an equanimity with that aversion, to get you through the rest of the sit - and finding out how to do that / that one is able to do that is a beneficial thing.

Something a friend pointed out to me is that he has never regretted doing a meditation session, even if it was a painful or drudgey session. I think the same is true for long sits - I ALWAYS feel like I've accomplished something worthwhile, and feel as if the day had something good about it, if I've done a difficult or long sit. Its one of those few things that is guaranteed to be non-regrettable regardless of the outcome, which I don't think can be said about anything else in life at all.

And yes I think they're especially powerful in daily life... the days where I do a full hour both morning and evening inevitably have a higher level of mindfuless and fulfillment to them. For me there is a standard of mental clarity that requires a daily minimum sitting time to attain to.

Try reclining or a comfortable chair if you can keep the energy up.

There is some benefit to sitting through pain but no need for heroics.

Thanks for the detailed responses all!  I love the input.  Teacher says he agrees with Daniel on this one- that likley what I'm doing will get me where I want to go.  That said, I'm interested in sitting longer, so I am giving it a go on my days off.  I think there are some definite benefits to be had after reading your comments.