I had 0000 as the newborn size, but my DD was so tiny when born (2.56 kgs) that those swum on her. Fortunately we were given some 00000s as gifts afterwards and Mum came down and stayed and bought us some more. She was in 00000 for about 6-8 weeks.

It sort of depends on the baby. I would keep at least a few 0000s, even if bubs is only in them for a very short while.