A Sales Trigger is the point at which the sale was made.

The Trigger is the Point of Pain for the Prospect. The Trigger is when the prospect decided to buy.

It could be what keeps the CXO up at night. Or it could be a benefit / productivity gain / convenience / ease that your product / service provides.  The Trigger is different in each sale.  Also, the salesperson (and especially those guys in Marketing) have one set of ideas on what the Trigger will be, but your Prospects will have a whole different set of Triggers.

Do you know what the Sales Triggers are for what you sell? Go ask your five top customers to find out what it really is.