Every few years. And combined with airfare, resort, etc.
I don’t like to waste money, and look for places to save… but also I’m willing to spend money to enhance a trip. I’ve upgraded to suites on cruises, club level at Disney, after hour tickets at Disney. An occasional special meal. On European trips, doing private tours instead of the large group tours, etc.
I’m guessing (purely a guess), that Disney’s goal of DPA is to regularly sell higher access to 10% of guests. (Lots of guests splurging for 1-2 passes… a small number buying it on every ride. But about 10% of guests using it moderately and regularly).