Princess will add $10.00 per person/per day to your onboard account for tipping of all staff. The following link explains their procedure in more detail.
http://www.princess.com/news/article...rticleId=na475
I, personally, still prefer to do my own tipping. Gives me the chance to tip more if I feel the staff did an outstanding job. I'm happy to say, that I've never felt the need to tip less than recommended.....our service has always been wonderful.