Handle expired SQL login's passwords in SQL Server
Complementing to Julien's answer, you can be proactive to schedule below tsql as a job to alert you on daily basis especially on DaysUntilExpiration of LOGINPROPERTY e.g. get all the logins from your database server that are going to expire in 2 days.

SELECT name as LoginName,
create_date as LoginCreateDate,
modify_date as LoginModifiedDate,
is_policy_checked ,
is_expiration_checked ,
-- returns the number of days until the password expires.
LOGINPROPERTY(name, 'DaysUntilExpiration') DaysUntilExpiration,
LOGINPROPERTY(name, 'PasswordLastSetTime') PasswordLastSetTime,
LOGINPROPERTY(name, 'IsExpired') IsExpired,
LOGINPROPERTY(name, 'IsMustChange') IsMustChange
From sys.sql_logins
--- optional filter 
-- where LOGINPROPERTY(name, 'DaysUntilExpiration') &gt;= 2