score:2
Each session is about 1 hour in courses organised in groups. E.g.
4:00 am Morning wake-up bell
4:30-6:30 am Meditate in the hall or in your room
6:30-8:00 am Breakfast break
8:00-9:00 am Group meditation in the hall
9:00-11:00 am Meditate in the hall or in your room according to the teacher's instructions
11:00-12:00 noon Lunch break
12noon-1:00 pm Rest and interviews with the teacher
1:00-2:30 pm Meditate in the hall or in your room
2:30-3:30 pm Group meditation in the hall
3:30-5:00 pm Meditate in the hall or in your own room according to the teacher's instructions
5:00-6:00 pm Tea break
6:00-7:00 pm Group meditation in the hall
7:00-8:15 pm Teacher's Discourse in the hall
8:15-9:00 pm Group meditation in the hall
9:00-9:30 pm Question time in the hall
9:30 pm Retire to your own room--Lights out
Source: https://www.dhamma.org/en/about/code
4:00 am Wake up
4:30 Meditation in hall
5:30 Morning discourse
6:30 - 8:00 Breakfast and rest
8:00 - 9:00 Group meditation in hall (for all)
9:30 Individual instruction (for all)
11:00 - 1:00 pm Lunch and rest
1:00 - 1:45 Meditation
2:00 - 3:00 Group meditation in hall (for all)
3:30 - 5:00 Meditation, and interviews for new students
5:00 - 6:00 Tea and rest
6:00 Evening discourse
7:30 - 8:30 Group meditation in hall (for all)
9:00 Retire
Source: http://www.internationalmeditationcentre.org/uk/guidelines.html
MORNING SESSION
03.30 – 04.00 a.m. – Wake-up / Dress-up
04.00 – 05.00 a.m. – Walking Meditation
05.00 – 06.30 a.m. – Sitting Meditation
06.30 – 08.15 a.m. – Breakfast dana, cleaning common areas, toilets and dorms etc.
08.15 – 09.15 a.m. – Sitting Meditation
09.15 – 10.15 a.m. – Walking Meditation
10.15 – 11.15 a.m. – Sitting Meditation
11.15 – 12.00 p.m. – Lunch Daana
AFTERNOON SESSION
12.00 – 01.00 p.m. – Walking Meditation
01.00 – 02.00 p.m. – Q&A / Dhamma Discussion (Every Day)
02.00 – 03.00 p.m. – Walking Meditation
03.00 – 04.00 p.m. – Sitting Meditation (Except the Last Day)
04.00 – 05.00 p.m. – Walking Meditation
05.00 – 06.30 p.m. – Dhamma Talk (Except the Last Day)
06.30 – 07.00 p.m. – Mindfullness Gilanpasa (Tea) Break
07.00 – 08.00 p.m. – Walking Meditation
08.00 – 09.00 p.m. – Sitting Meditation
09.00 p.m. – End of Day’s Program
All the access doors to the meditation premises should be closed and the lights should be turned off by 10.00 p.m.
Source: http://www.nissarana.lk/meditate-with-us/retreat-timetable/
If you are tailoring a private course for yourself maybe you can have longer sessions.
The time tables are set so both new and old students can meditate in reasonable comfort. There is nothing to worry about the time of the session lengths as many meditators do not find this an issue.