Most people work better with shorter, more frequent study periods. Or with breaks during longer sessions. Think of it like interpreting, a complex task requiring alertness, multiple-tasking and processing, and physical strength and stamina. It is common for assignments over two hours to be shared by a team. This is because we acknowledge that our effectiveness as interpreters is compromised after long periods of work.
Most teams rotate every twenty to thirty minutes.
This is based on research about the effectiveness of interpreting over time. The twenty to thirty minute rule might be a good one to try in your study schedule. Don t procrastinate. Cramming is not real learning. It is only trying to remember a large amount of material for a short period of time.