Michelle - Gabby was almost 1 month old before she started sleeping through consistently. I know that the experts say that 5 hours is sleeping through so, for Gab, it was probably earlier.
She started off having 4 hour sleeps, then it got longer and longer. For a while she was 8 hours to the dot just about! Now she has 10-11 hour sleeps at night but is awake most of the day.
They change so frequently and every baby is sooooo different!