| | Hi Daniel I've thought about this question a lot also It seems to me that it depends upon your own life circumstances and your own particular traits. I think experimenting would be the only way to find which ways work best for you.
Having said that, I guess the three most important things to keep in mind are:
1. generally, sitting for longer sits is supposed to allow you to go deeper, especially in terms of concentration. so for example if you don't have any problem sitting for 1 hour, then it would probably be much better to do so that than to do 2x30.
1.2 sitting for too long is probably counter-productive if you try to sit beyond your own effort-energy levels
2. there is certainly something to be said for starting and ending the day with meditation. ie. continuity of practice.
I guess that is why Goenka recommends an hour morning and evening, it allows a generous amount of time to dig into the practice, while also giving a certain structure and continuity which binds your practice to your daily life (starting and ending the day in dhamma). Neither 4x30m and 120m sits have these two benefits, they either focus on the benefit of deeper sitting, or of continuity of practice.
I think that another reason for having an hour sit in the evening, in terms of Sila, is that it requires you to intend to not be fatigued/conserve your energy so that by the time evening comes, so you can complete your evening sitting (and I imagine that in terms of Sila or at least health, it's not good to end the day fatigued). |