I use avent for 5 years la
the children use them very good. and I think its ggod to be not so soft cus too soft will make the tid easy to collapse. When they drink to vaccum they know is time to release the tid.
I never think about how many times I only steam the teats once before my son used it. No problem. Babies are not as fragile as we think, just let them try , they can do it.