Picklists provide users various options when they choose to fill a certain field in a Salesforce object. Their biggest advantage is that since they provide prebuilt options, chances of errors are reduced, and the data also remains clean and can be easily parsed. To further make picklists more advantageous Salesforce provides dependent picklists in both Salesforce Lightning and Classic versions.

Dependent picklists allow the contents of a picklist to change based on the value of another field on which they are logically dependent. It not only helps limits the options that are available to a user when filling a field but also shows the more relevant options in a picklist thus, making it easier for users to work with Salesforce.

Using dependent picklists helps ensure that users enter accurate and consistent data. A dependent picklist can be defined as a custom or multi-select picklist for which the acceptable values depend on the values mentioned in another field, which is known as the controlling field. Controlling fields can be any picklist (with at least one and fewer than 300 values) or a checkbox field with the same record.