I used these bottles repeatedly every day because I was raising my daughter and son with a combination of breast milk and formula. Even so, they are made of glass and are durable, so there are almost no scratches or signs of wear. It was very convenient to have several bottles because I had to wash and sterilize them several times a day. These are keepsakes from the days of raising my babies, and I hope they can be of use to someone else. *Please note that the lids and other parts have been disposed of. Thank you for your understanding.