Does the ruling on masturbation in our era differ from its ruling in the past, or does it remain constant, and what is its ruling out of necessity and otherwise?

The validity of a jurisprudential rule and its application are not necessarily identical. The issue of a fatwa changing with the change of time, place, circumstances, and customs is established, but it is not absolute. If a Shariah ruling is based on the custom of a land and that custom changes, or if the ruling is based on a specific meaning and that meaning changes, or if the ruling is specific to a particular place and time, then it is permissible for the fatwa to change. However, Shariah rulings that are based on religious evidence and are not built upon custom and tradition do not change with the passage of time. The ruling on masturbation does not change with the passage of time because it is ثابت (established) by Shariah evidence, not by custom and tradition.