Because you will have the same stateroom host every day, there is no need to leave gratuities daily.
Near the end of the cruise, you will be provided with tip envelopes for your stateroom host, dining room server, assistant server, and head server, with slips showing the amount of prepaid gratuities. If you want to the change the amount, guest services can make the adjustment and provide you with updated slips. You can also put cash in the envelope if you prefer. We typically give the tip envelope to our stateroom host when we see him or her on the last afternoon or evening of the cruise, and look for the host in the morning if we didn't deliver the envelope at night.
Technically, the envelope is not even necessary if the tip has been paid electronically, but presenting it gives us the opportunity to thank our host for the excellent care we always receive.