I think for newborns sterilisation is a MUST, especially those born early or with compromised immune systems. If sterilisation wasn't considered important then Hospitals wouldn't be doing it themselves. Just remember that there are many 'bugs' out there and it really doesn't take much for one to enter their blood stream. I gave birth to a healthy baby boy and at just 4 days old, whilst still in hospital he caught a very rare 'bug' and ended up with Meningitis. After seeing him fight for his life, which thankfully he won, I was very particular about sterilising everything and washing my hands thoroughly. Unfortunately there aren't vaccines out there to cover every 'bug' and these 'bugs' are everywhere, they're in the noses and throats of people, in the water, on your hands etc, but if you can prevent them from being injested then why wouldn't you, it doesn't take much to sterilise a few bottles for the health of your baby.