Remember TiW is for eligible Florida Residents, Disney Vacation Club members and Annual Passholders that cost at least $75.00 on top of your Annual pass. It's a great deal if you are going to Disney more than once. Unless someone on the boards will lend you theirs..lol
So like everything in Disney, it depends on your vacation habbits. As for your eating habbits, where do you want to eat? You get three TS a day under the DDP. I think three meals a day is a lot of food. However, if you want to do a Signature meal a day, then three TS may be okay. Our next trip, we are adding the DDP so to have a Signature meal a day. We love Fulton's so that alone will save us. You have to work the system to get the best value.
I always use the dining plan as it's proven to save us money. The savings has decreased over the years as the dining plan has raised in price more than the cost of our food.
There is never a need to waste snack credits. The last day of your trip go and stock up on some snacks that you can take home. I always go to Earl Sandwich and stock up on cookies. It great when you get home and have the post Disney blues to pull out a Disney snack.
It the end, Disney makes enough discounts that you need to do a little homework to see what works best for you.