okay, here's my
disney dining plan primer...
once you check in, all of your dining credits are tossed in a pool... there is no "daily" limit, there is a "vacation" limit, based on your number of nights... so, if you are 4 people staying 7 nights, you will have 28 Table Service* meals in your bucket; 28 Counter aka Quick Service** meals in your bucket; and 28 snacks*** in your bucket... you can use them any time, any day, in any order that you wish... however, they expire at midnight on the day you check out...
*Table Service meal... any place you are seated and tended to by a wait staff (menu restaurant, buffet, family style, etc) is a Table Service meal... and most TS meals "cost" one Table Service or Sit Down credit per person (there are some exceptions like the dinner shows and high-end aka Signature Restaurants)...
**Counter aka Quick Serve meal... fancy names for food court meals... if you carry your own tray (in 99% of the cases) and scramble for your own table and have to clean up after yourself, it's a QS meal...
***Snacks... pretty self-explanatory... ice cream, soda, water, popcorn, pretzel, fruit, etc type food... single serving only... typically under $4... it's a Snack...
Room Service... ahhh, Room Service... category all its own, but can use some of those Table Service credits... however, each meal "costs" TWO of those TS credits and the allotments are similar to those at TS restaurants (i.e. entree, dessert, non-alcoholic bev)...
Pizza Delivery is also considered "Room Service" and costs TWO ADULT credits (no matter who is eating it) and comes w/soda and dessert...
Now, once you have used all your credits, you may pay out of pocket or charge to your room... if you want Room Service and don't think it's worth the two credits, then you can pay or charge as well, even if you have credits available...
It's somewhat flexible and easy to use, once you wrap your head around it... keep asking if it's still not clear!