1. Personal preference: Some people like the upper berth, because it can provide a relatively private and quiet environment, suitable for people who need more personal space. The lower berth is more suitable for people who like to interact with their roommates socially.
2. Health condition: If you are unable to move or feel sick, it may be more convenient to choose the lower berth, because you can get in and out of bed easily. The upper berth may need more climbing movements, which may be more difficult for people with poor physical conditions.
3. Security: The upper berth is usually safer than the lower berth, because the lower berth is more easily noticed by intruders. In addition, it is easier to avoid being accidentally kicked or touched by roommates in the upper bunk.
4. Cleaning: The lower berth is more vulnerable to dust and stains, because the ground is more exposed to these pollutants. The upper berth is cleaner because it is far from the ground.
5. Privacy: The upper bunk usually provides better privacy, because you can draw curtains or use curtains to block your view. The lower berth is more easily seen by roommates or passers-by.
6. Noise problem: The lower berth is usually disturbed by more noise, because the sound of roommates' activities is more likely to reach your bed. The upper berth is quieter.
To sum up, the choice of bunk beds should be based on personal preferences, health status, safety requirements, cleanliness requirements, privacy requirements and noise tolerance. The most important thing is to choose a bed that can meet your personal needs, so as to ensure that you can have a comfortable and pleasant living experience in the university dormitory.