Mostly I book when I see a good deal. Not just Dinsey. If rack rates are/were good enough, I'd book. But $600 a night is too much for any WDW resort. It's not so much that I require a discount, as I have in my mind what I'm willing to pay. When I see a price I like, I book. Usually that means a discount.
Take the choice of getting a rental car or airfare. If I see an an airfare deal, I book. If not I drive. Same with a rental car, if I see a price I like, I book. If not, I do without. I'll pay say $100 for a car for a certain duration, but not $600.
If I don't see a price point I like, I skip it.
If I see a better deal, I will rebook at a better discount, but I don't see it was work, so much as extra money, or an extra day of vacation.
If the economy is bad, Disney offers discounts. When the economy is better, they offer less. I think over the last ten years though we've always got some kind of 'discount' on at least part of our vacation. If there are no resort discounts, then I buy discounted park tickets from
UT or
AAA, and I play with dates to get the lowest airfare. I just sort of see it as kowing what's out there.
I also don't get alll the DIS hype though....