How often do we need to change milk bottles (not teats)? My milk bottles have turned cloudy from the sterilisation, wondering if it is necessary to get new bottles.

It is adviced to change every 3-6 months because it can get hairline cracks that can't be seen with the eye - especially if you only have a few bottles or keep warming and/or sterilizing the bottles. I change every 3 months, or as soon as the wordings start to fade away!