Infant insert for Ergo?

Do I need to purchase the infant insert aswell? My boy is 12 weeks. I can't find anywhere that tells me what age the insert is needed til.

It says somewhere to use the infant insert for up to 4 months old. I just bought one myself and i do remember reading this - not sure where though but it was definately 4 months.

The insert is really only a padded blanket anyway so depending on the size of your boy you may not need it.

I wouldn't bother. I had one, never used it. Ash was too big for it and my boobs were way too big, there wasn't room for it. I just froggied him until recently, and he is 4 months now (I think from about 3 months he was in it normal with legs out)

It is recommended until four months. However, I used an Ergo without the insert from just over three months, as my DS had good head support. Although it mostly depends on how tall your baby is, my DS was very tall, and could comfortably sit upright with legs spread without the edges of the carrier digging into the back of his legs.