I agree with most of the other replies that $10 per day is not all that much. If you tip within the norms on a land-based vacation, I think you will find that you tip at least that in restaurants and for the room attendant in most hotels. In addition, I have found the service to be a bit above average on a ship and I have not sailed on the "premium" lines. Someone did mention the tax angle, and I agree that having a standard service charge does mean that it is probably taxed as income. However, most ships have foreign personnel and we have no idea how much these people were getting charged to convert their USD into their home currency. It could be worse than the taxes they pay on the set amount.