How do I ensure quality data in Salesforce?

Set appropriate standards for data quality, including the ability to measure or score records. Put a value on age, completeness, usage, accuracy, consistency, and duplicates, along with any other quality or value metrics specific to your business. Active leads are updated at least once per month.

What type of rule does Salesforce make available that helps improve data quality by preventing users from saving a record with bad data?

Validation rules verify that the data a user enters in a record meets the standards you specify before the user can save the record. A validation rule can contain a formula or expression that evaluates the data in one or more fields and returns a value of “True” or “False”.