When do i stop sterilizing my baby's bottles and boiling water for baby to drink?

Usually pretty soon: A baby who lives in a clean environment, with clean parents, clean tap water, and a great sewage system, doesn't need to use sterilized water or bottles after the first 2-3 months. Sterilizing adds a tiny extra margin of safety, but is a lot of work. Many parents will use bottled water or still boil their water, in case the city water has some microbial spores, although this is rarely a problem.

Rarely Need to Start: True sterilization is usually not done with the attendent need to wear protective gear, gloves, etc.In the old days and in 3rd world areas, this is still beneficial, but in our world, probably not needed. The only exception I am aware of, is the use of well or bottled water where boiing the water should take of any bacterial contamination.