Problem: Have you ever wanted to see a list of related grandchild records when viewing a parent record in Salesforce? A simple example of this would be to display a related list of Cases or Opportunities created for all child Accounts at the parent Account level.
Creating this relationship manually may be very difficult because the parent Account name may be unknown at the time of Case or Opportunity creation. What ends up happening is your users spend unnecessary time trying to figure out if there is a parent Account, and if so which Account it is.
In this example, we'll walk through relating Cases to Grandparent Accounts, but you can use this method for other Objects.
In Setup, create a lookup field on the Case object. Call it something like "Grandparent Account."
In Lookup Helper
Select Case as the Child Object
Use the newly created Grandparent Account field as the Lookup field to be used.
Set Child Case Field as Account (accountid) > Parent Account ID
Match to Parent Account field: Account ID
Save and run your Lookup Setting
Now your Cases will be automatically related, instead of having to manually find parent Accounts.
Note: This use case is only for grandchild records, but it is possible to go more than 2 levels deep with an additional formula field used as a matching field.