What is TDTM and how is it useful?

NPSP has many objects that connect with each other, so there are many automations coded into the NPSP package. TDTM provides an admin-friendly declarative interface to reorder coded triggers or to disable triggers entirely. Your first question may be: what is a trigger?

Let's do a quick overview of triggers and how they function.

Triggers are snippets of code that run in response to something that happens and are a part of the programmatic side of NPSP that is Apex code-based. When you do programming with Apex code you can do almost anything within Salesforce as long as the functionality stays within the governor limits. It can also be more performant than declarative tools. However, changes usually require a developer, a sandbox instance, and unit tests.

So, TDTM is really a set of records within an object (trigger handler) managing automations related to triggers. In accordance with best practices, TDTM provides one trigger per object...