Tipping
Tips are THE "required" payment item you will run across on the ship. You have paid for all other "common" activities. The wait staff and room stewards are paid only a very small amount ($50/month) by
DCL. The rest of their wages come from tips. The DCL brochure has a chart of recommended tips for each person to be tipped (others have posted this info on threads regarding tipping). The amount listed is PER PERSON.
I really believe in tipping these folks generously. They work hard to make our trips magical and memorable. With you having two 1 yo's with you on the cruise, I'm not sure how I feel about that PER PERSON tipping for the wait staff. For your room steward, I would think that tipping even for the babies seems reasonable, since they will be cleaning up after you all.
There is an opportunity to tip when arriving and departing from the port. There are porters available to help you with your bags. They don't get paid, so they are working for tips (1-2 bucks per bag - more if they are taking you way out to the far parking lot).

Anyone else with thoughts on tipping the waitstaff "by" babies/very young children? If you think it's OK to not tip for the babies, at what age do you think it becomes "manditory"
Other Stuff
With your young ones, you may want to take advantage of Flounders Nursery. They watch the babies for a fee. Don't have any babies, so don't know how much they charge and how long / many times you can sign them up for.
Since you don't plan on shore excursions, you will be saving a lot of money. Beware of Shutters (the photo place)

That's where our budget goes to heck. We walk through, look for our pictures and usually cannot resist!! The photos are 6x8 or 8x10. Pretty spendy!!
If you don't "drink" much that will save on your alcohol bill. There is a wine tasting "class" that has a charge if you are interested. The spa, arcade, speciality drinks have a charge (Coffee, water, ice tea, lemonade, punch do not and soda doesn't at dinner), snacks/junk food for purchase outside of the Walt DIsney Theater (why would anyone want to buy this stuff - when there is a ton of nummy food available for "free" - like the ice cream, chocolate chip cookies), and the other "snack" food up on deck 9?
So what does that leave to do for "free"
Swimming, the kids age 4-18 in their clubs, ping pong, shuffle board, shows, movies, relaxing in a deck chair, the "adult educational series" (Navigators, Art of Entertaining, Art of ENtertainment), Activities (like racing a vegitable car, golf chipping tourney, learning to draw Disney characters, family kariokee, game shows, etc), demonstrations: ice carving, bridge tour, galley tour, the "art of the ship" tour, eating, relaxing, whispering "sweet nothing's" to your sweety while walking around deck 4, there's the sports deck up on deck 10 (basketball, volleyball), the sail away parties, and the list goes ever on. Lots to do, not enough time to do it all and this part of the list is 100% free for the price of booking the cruise.