(Version 11 or later)
Event handlers are a very lightweight method of providing a means to adjust tags and custom functions where you need to persist data from one call to the next, such as a running total across calls to a custom function.
Pods let you create a template without recreating a tag. Instead, you use an existing template's tags and tables to create new tags for other templates. You then simply drag and drop these pods into a new template.
The debugger steps through running a template. You can stop on tags as they are applied to see what action they take and why.
This is template debugger that can help you determine why your template is not generating the report you expect.