What shared common area means in practice
Common areas are where most shared-housing friction, cost, and condition disputes live. They need their own house rules, their own cleaning responsibility, their own line in the inspection record, and a clear statement of which costs are shared, because mess or damage there usually cannot be attributed to one resident.
Example
A move-out inspection records the private bedroom separately from the kitchen and living room, so a shared-area cleaning charge is not applied to the wrong resident.