For convenience, list values may be maintained from several places:
Lists values may be dependent upon values in other lists. This is termed Allowed Values, and is covered in more depth in the Allowed Value page within the Site Configuration section of this guide.
Within all user defined field lists, there is the opportunity to disable a value. Once the value has been disabled, it will not appear in any screen in a selectable manner. If an existing record already has the value set, then the user may leave the value in place or they may select a new, enabled value.
Note that checkbox fields are stored internally as lists that are constrained to just two values, typically Yes and No, On and Off or something similar. You may not disable a value within a checkbox field.
Interest Lists are also maintained for field values within List maintenance. For example, if you want to maintain an interest list for a specific product, or an interest list for Priority 1 issues, then this may be completed through the add and edit functions of each list.