There's only one answer for this, it depends. It depends on several things. What do you want it for? Do you think you will save money on it, or do you just want to feel like you don't need to look at prices on menus or whip out your wallet to pay for meals? For some, even if it's unlikely they will save money, they want it for the freedom they believe it gives them. As for saving money there are a couple of questions to ask yourself about your

Do you have children under 10 years old? Do you intend to have at least one table service meal every day of your trip, and make that meal lunch or dinner (not breakfast)? Do you concentrate on buffets, character meals, family style or fixed price dining? Do you vastlyl prefer the signature (2 credit) restaurants? If you do, you might look into the deluxe plan. If you can answer the first 3 questions "yes" then you might as well get the plan because you will at least break even. Here's another set of questions: Are you happier just stopping off at counter service restaurants when you get hungry rather than trying to stick to a mealtime schedule? Does your party tend to share meals, skip desserts or order free (not bottled) water as your beverage? Do you have picky or very light eaters? If you say yes to the these questions, it's unlikely the plan will save you money, so get it only if you want that all-inclusive feeling. It's always based on nights - depending on which plan you purchase you will receive credits based on 8 nights. On the regular plan each person is allotted 8 QS, 8 TS and 8 snacks.