Tipping is relatively new in Bali. Some restaurants will automatically add a service charge of between 5 & 10 percent to your bill while almost all hotels will add 10% to your bill which is quite sufficient. In such instances the service charged is added then an additional 10% government tax is assessed on the total (bill plus service charge).
However many smaller restaurants generally don't add anything extra for service but considering that the waiter's wage may well be less than $2.00 a day - a tip of 5-10 percent is very much appreciated.
Other tips. Bellmen generally get Rp.3,000 for a small carry-on sized luggage, Rp.5,000 for larger bags and Rp.10,000 for extra heavy luggage and for those house trailers some people lug around. For taxi drivers, rounding up to the nearest Rp.5,000 or 10,000 (depending on the length of trip) is the norm. If you hire a car for an entire day it is good form to give the driver Rp.10,000 - 15,000 for each meal and tip (say Rp.20,000) at the end of the day. With tour guides and the like tipping is up to you - bear in mind that chances are your driver/guide has most likely already received a commission from anything you purchased during the day.