Change the Default Number of Records Shown On Unexpanded Related Lists on Salesforce Classic User Interface

There is currently no org-wide setting within the application to set a default number of rows on related lists for object page layouts (Related Idea: Change number of records visible in related list).  Rather, this is a User by User preference, that can be set for all object page layouts.

To do this in the user interface, view any record detail page.  Scroll down to the bottom of the page, after all of the visible related lists.  On the bottom of the page, you should see some text on the page that says: "Always show me fewer / more records per related list"

A user can click on the fewer / more option to control the number of records that will display in their related lists for all objects.  Clicking each, will decrease/increase the current setting by 5.  If a user has a certain number of records in mind (from 5 to 100), and does not want to click manually on the fewer/more links, this can be done more quickly by using the URL for this setting.

For example, if you were on a Case detail page, you could plug-in the URL below (X = instance and ID variables, 50 is the number of rows you want to display)

https://naX.salesforce.com/xxxxxxxxxxxxxxx?rowsperlist=50

The example above would set the default per related list for all objects to 50.  The next time you visit another record detail page (on any object), and click on the fewer/more links, the number of records displayed decrease/increase by 5 from the value set in the URL, in this case to 45 if decreased, or 55 if increased.

-This setting (either done via the UI or the URL) is sticky and will remain at the number of rows you define unless manually changed. This is true for navigating away from the page, viewing another object record or logging out of the system
-The minimum number of rows that a user can define is 5. Anything lower will default to 5
-The maximum number of rows that a user can define is 100.
-This resolution is for Classic View and not available in Lightning View