回複：我覺得樓主有報複心理。房東沒有過錯，但罵人不好。

Generally speaking, if the lease starts on 4/1/ 2010, for a one-year lease, the expiration date is 3/31/2011. It is the tenant who will lose some hours.

Some nice landlord will give the tenant the key in advance, however, it is not required by law.

There should be an agreement/lease between the landlord and tenant regarding when and how the key should be returned. Some nice landlord will give the tenat extra hours (the whole night of 3/31/2011 in the above example), and some are very strict with the midnight deadline. However, before the midnight deadline, the landlord has no right to enter without prior notice except for emergency issues.