Hi, Laurice!
The first thing to know about buying a
Walt Disney World annual pass is don't buy it for the discounts. There are
Passholder discounts on some things, but these can change. The 20% discount on dining was a special promotion, and while it is no longer available, you will still get a discount on many dining experiences. The discounts range from 10-20%, vary by location, and some are available only at lunch. You may luck into an annual Passholder room discount, and you do get free parking at the theme parks, but the best reason for buying an annual pass is because you'll visit the theme parks enough times to make it worth it.
The main reason I tell people to consider a
Disney Dining Plans is so that you know in advance about what your food budget will be. Once you prepay that dining plan, you will have a good chunk of your meals paid for, and that's much less to worry about out of pocket when you arrive. Do the plans save you a lot of money? It depends. The biggest bang for your buck is to order only the most expensive things on the menu - the steaks, the seafood dishes, etc. You won't save much money if you order the less expensive items. But some nights, you just feel like a pasta or a chicken for dinner. That may be the night you don't use your credits so you can splurge on a two credit meal later, but you have to calculate all of that out. Some people save a bunch, others break even.
I hope this helps you with your planning!
Anna