When and how would you implement custom settings versus custom metadata types, highlighting their specific capabilities and limitations?

Choosing between custom settings and custom metadata types in Salesforce depends heavily on the nature of the data you need to store and how that data will be used. Both offer ways to store configuration information, but they have distinct characteristics and are suited for different use cases, with specific capabilities and limitations that influence the decision-making process. Custom settings are designed to store application data that may change over time, or is specific to a user or a profile. They behave very much like custom objects, but with the added benefit of being cached, providing faster access to data. They are ideal for storing configuration data that needs to be easily updated by administrators or users without requiring a code change. There are two types of custom settings: list custom settings and hierarchy custom settings. List custom settings provide an organization-wide set of values, whereas hierarchy custom settings provide data that is specific to a user, profile or organization. They also have a limit on the amount of data that can be stored. For example, suppose you have a requirement to store the currency conversion rates for different regions in your organization, and that rate is updated every month. In this case, a list custom setting is an excellent option as the values may change frequently and it's a straightforward way to store it and access it in Apex code or validation rules without the need to create a custom object and create SOQL queries. Another example would be to store email template IDs for sending notifications in Apex code. Also, you can use hierarchy custom settings to store profile or user specific data like....