A great HBR piece on NPS in context:
1. break down activities along value chain (e.g. if you're a hotel: reservation, check in, arrival in room, etc.)
2. identify WOW moments and leverage them (e.g. as an opportunity for recommendation)
3. identify weak links and fix them (improve operations or comms--e.g. how you frame the experience)
"Most customer surveys, including NPS, are conducted at the very end of a purchase and consumption experience. Retailers send surveys after a purchase has occurred. Manufacturers wait a week or so for customers to use the goods before hitting them with a survey. Hotels generally approach guests at check-out or a few days after they leave.
The idea is to have consumers experience the entire process, then gauge the overall experience... ...If your company delivers on more than one activity in the customer value chain, you should measure customer satisfaction after every activity (offering the survey randomly to subsets of customers to avoid survey fatigue). This will allow you to identify the WOW! moments and leverage them to your benefit. It will also enable you to find the weak links and reinforce them."
(LinkedIn post 2019)