Problem
You want equipment to be automatically added to invoices when certain service tasks are used in ServiceTitan.
Solution
Automatically attach equipment to tasks
Go to Pricebook.
Go to Services.
Edit the service you want to add the equipment to.
Go to the Equipment tab.
On the Equipment screen, select the item or items you want from the category dropdowns to be automatically added when the task is added. There is a list of all equipment to be added on the right side of the screen.
When finished, click Save.

If you want to attach materials to tasks automatically, go to the Materials tab. This workflow also allows you to add membership plans and other items.
This method streamlines the process of building equipment history for replacement sales and other purposes.