We had to move the twins out of our room MUCH earlier than I cared to (or was planning.) Baby girl B was NOISY. So so noisy. I check on them, all of them, a lot. I’m such an awful sleeper so anytime I’m awake I go in their rooms.
Wrote about this very thing here..
http://chosenchaos.blogspot.com/2011/08/crazy-is-as-crazy-does.html

We ended up booting baby way before I thought we would, as Baby thought I was the all-night diner. She was over 6 mo and still waking to feed every 2-3 hours. I was at my wit’s end. So we moved her into her own room and she started sleeping through some of the feedings, only eating once overnight now. If I check on her, it is only until I go to bed, and even then I am VERY quiet when I do.

My kid got booted because he’s such a light sleeper, my husband’s tossing and turning woke him up all night long before he was even two months old and nobody was getting any sleep. I never checked on him much – he let me know when he was awake and needed me. Now, at 16 months, I check him to make sure he’s covered before I go to bed, but other than that, I don’t dare open his door unless he’s already awake for fear of waking him up. The stinker sleeps like a rock at daycare, sharing a room with other kids, but gets woken up by his door opening at home.

Um, apparently I am in the minority because I monitor stalk the crap outa my kids with the video monitor. :)
Never go in though, they are insanely light sleepers, which is why I was eventually forced to move them from my room. Approximately 10 light years after Cody would have booted them out – I only got away with *that* because my husband was deployed. He would have been just like yours. :)

Other than checking on my baby before I go to bed, I have to say I have never really been one to check on her during the night. When she was tiny and brand-new I didn’t feel the need to check on her because I knew I would be up feeding her every 3hrs. and that was more than enough “checking” for me! Can’t imagine waking for night feedings and waking just to check. That’s a whole lot of waking and not enough sleeping.

Now that she’s older (7 months) and sleeping through the night, I only check on her before I go to bed. I use a baby monitor and turn it up pretty high, though so I feel like I have a sense of what’s happening in there. I have to say, mothers intuition is certainly real and I pretty much count on that. Once, when she was younger she managed to roll and wiggle to the other side of the crib (for the very first time) and pull down a quilt that was folded over the crib railing (way past where even her little feet should have been). The quilt landed on top of her and she kind of gasped a little when it covered her face and just the sound of that gasp on the baby monitor woke me immediately. I literally sat straight up, jumped out of bed, ran to her room and pulled the quilt off seconds after it happened. Ever since then I have felt more confident in trusting that, as a mother, I will sense when something is wrong or when I need to go to her. Besides that, I don’t check too much or worry. :)