"LoopyNZ" wrote and I snipped:
DS (3.5 months, healthy weight gain) has been sleeping technically through
the night (5-6 hours) for a while now.

Last night he slept for 8 hours, and while that's a nice occasional treat
for me, I'm inclined to think it's probably a bit long for such young baby
and my breasts to go without a feed on a regular basis. Thoughts?

I think you should count your blessings if you manage to get 8 hours of
uninterrupted sleep at your son's age. My DD literally slept that long only
once before the age of 21 months when we night-weaned her.

I would only wake a sleeping baby to nurse in the night during the first few
weeks. And some wouldn't do it even then if weight gain was okay.

Enjoy your sleep!
-Patty, mom of 1+2