Bella - you will know if you have the BPA free one's as they are a slightly yellowy colour - not the clear plastic. I have been using a mix of the normal Avent one's that I had before I ever heard anything about BPA and also now a couple of BPA free Avent one's that I have since purchased. I tend to rotate them trying to use the BPA free one's the most.

I believe (and someone can correct me if I am wrong) that the time to get worried is if your bottle becomes cloudy - that is the time to discard.

Perhaps you could do like I have and grab one or two of the BPA free ones and use in rotation - all the attachments work with them just the same.

Janie xxx