How do I add or change a responsibility type?

You can add, change, or inactivate existing representative types using the PER_RESPONSIBILITY_TYPES lookup code on the Manage Common Lookups page in the Setup and Maintenance work area.

Is there a limitation on the number of responsibility types I can define?

Yes, the fewer the better, but in general you want to stay stay well under 500 values. For more information, see Areas of Responsibility Lookups.