Thank you for viewing! Purchased in April 2025. Used for about a month. I used it with 8 bottles for exclusive formula feeding, so I used it about once a day. I also outgrew it quickly, so I think the frequency of use was quite low. It's steam sterilized, so there's no yellowing. I will wash and sterilize it before shipping, but please re-sterilize it upon arrival. *Simple packaging, will be sent via post. Please note that the nipple tips will be compressed for packaging.