We were debating purchasing one, luckily we did as our baby was only 5lb, whilst she looked tiny in the inlay, she was fully supported and cosy. She has used the inlay until 8 months old. It has been easy to fit and remove for cleaning, and easy to wash too, it also wipes down easily in between washes (extremely sicky baby)
Required from birth to 4 months. Worth every penny as makes newborn look more comfortable and secured in car seat. Very easy to put on and removed also washable if gets dirty. I used this till my daughter was 4 months old as she was very small.