Jody:
The short answer to your question is 'yes,' you can use twice as many credits on one of your days so you won't lose your credits.
To elaborate, the beauty of the
Disney Dining Plan lies in its flexibility. You can spend your credits any way you'd like during your vacation. When you arrive, your MagicBand will contain all of your party's dining credits on it in one lump sum. You determine when and how you want to "spend" them! If you have the basic Dining Plan with one quick service meal and one table service meal per day, I recommend combining two of your credits for a Signature Dining Experience (see your dining plan brochure for these restaurants) or a dinner show like
Hoop Dee Doo Musical Revue or the Spirit of Aloha Dinner Show because they require two credits and you have enough to cover it.
If you have the Quick-Service Dining Plan, consider using your credits for items in the refrigerator case of many of restaurants to purchase a pre-packaged meal like sushi, a sandwich wrap or even a salad. You can keep it in your room's refrigerator and enjoy it on your departure day either in your car or at the airport.
Wishing y'all a magical vacation!
Whitney