No, you are not expected to tip during sit down or buffet lunches or breakfasts. The way the cruise industry works is all the tips are given on the last night of the cruise (except if you are at Palo then you can give your tips to your servers at the last breafast before debarking.
No one will look at you funny so don't feel you have to leave a tip for lunch...it is not like a land based restaurant and the servers are not expecting to be tipped at lunch or breakfast.
You do tip for room service...$1-$3 bucks depending on how much you order...it is at your discretion.
Any beverage you purchase will already have a 15% gratuity added on so don't tip above that unless you really want to or build a repore with a particular bartender.
We just cruised on the 9/18 Eastern and if the service was good at lunch, which it always was, we left $5. We figured they deserved it and we didn't want to hope that their regular night time guests were gonna tip them good.
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