Oracle 11 Password_life_time

It is good to remember that in Oracle 11 "Password_life_time" resource in default profile is 180 days. So if you create new user in Oracle 11 and do not set other profile to that user then this new user password will be expired in 180 days. Thought you can change this default profile setting like this:
SQL> ALTER PROFILE default LIMIT PASSWORD_LIFE_TIME UNLIMITED;
You can check all profile limits from here:
SQL> SELECT * FROM dba_profiles;

Remember also that when you create new database in Oracle 11 all it users get default profile by default. So they have Password_life_time 180 by default.