You don't get charged unless your carry-on must be placed in an overhead locker.  My brother's family (of five) just flew from PHL to DEN and fit all of their belongings under the seats in front of them.  They are not exactly savvy travelers, either--the youngest, at 17 years old, had never been on a plane before.  I check a bag or require the overhead lockers probably once a year.

Labels: moderation: safe