DH and I have been on 4 cruises, only 1 on
DCL. We feel like the server/steward, etc. budget their money and depend on getting the minimum amount recommended. If they only do their job and nothing else, that is what we give them. Now, if they do a great job, are more personable, ie. towel animals in our room or remembering that I like the cheese course first and not last at dinner or remember our drink preferences (you get the picture), we tip more. We've learned by experience that tipping the bartender, on the spot, every other drink or so, our drinks are stronger. On
RCCL we had a poolside waiter that was also a bartender we only ordered our drinks from him and each drink had an extra side to it

We also tipped him more at the end of the cruise. He worked his butt off to remember passengers names, drinks, etc.
Anyway, to answer your question. On our 7 night cruise in Jan. our family of 4 will bring at least $100 per person for the recommended tips so $400, but probably $450. We'll bring about 50 - $1 coins for room service, bartenders, poolside wait staff, etc. For the kids clubs staff, it seems like they like the wal-mart gift certificates so we'll bring some of those as well. Our tipping budget will be $500.
Hope this helps
Staci