Even there, doing the financial analysis is unnecessary. Is Disney going to sell you a product where the numbers don't work out? DVC wouldn't sell if the numbers were grossly unfavorable. They need to be able to make the pitch that this will save you money - and they are legally obligated to have at least some truthiness to that statement - they need to be able to justify their advertising statements. Disney's sales pitch calculations are pretty darn favorable - and decent. So why bother going to the effort of doing them yourself? On paper, the product is going to save you money, or Disney wouldn't have a successful pitch. (And the answer to the question is, some people, including myself, have fun doing this sort of analysis. But using it for decision making is dangerous. Because if you know what you are doing, you don't need someone else to do it for you - you probably delight in running the numbers and changing the assumptions. And if you don't know what you are doing, you don't know enough to realize the weaknesses of this sort of analysis to understand what assumptions underlie the analysis.)