Dorms
sharing a room
sleeping
woken up at night
woken up in the morning
snoring
safety
lockers
socialising
cleanliness
drying clothes is a bit harder, without encroaching on the space of others.
shared bathrooms
limited shower space
running out of hot water
costs
Private
sometimes cheaper for two people.
cheaper for one person
different lifestyle - see "Life in Dorms"
noise / decent nights sleep
on the road for months - sleepless nights start to add up
single sex vs mixed