What age do babies 'sleep through'?

[toebeanz]

And what does sleep through actually mean? 8 hours?

Ftm and very sleep deprived.

Mine is 3.5 years and still not sleeping through!

From about 12 weeks old my DS would sleep from 10pm to 6am. I would say that was sleeping through. From there it went to 9pm to 6am, 8:30pm to 6am, 8pm to 6:30am then by the time he was 18 months old he would sleep 8pm to 8am with one nap in the day which he dropped at 2 years old. He's three now and generally sleeps 8:30pm to 7:30am with bed time being 8pm