I always swore I would never co-sleep. Not because I didn't like the idea of snuggling up to my kids, but because I was worried that I would have an 8 year old still in my bed EVERY night.
When Jullien was a baby, I would pull him in the odd time in the wee hours of the morning - I would nurse him and it would buy me an extra hour or 2 of sleep.
As he got older, I stopped doing that, as I didn't want it to become a bad habit.
Fast forward a year, and J started working nights (5pm - 3am) When Julien would wake in the middle of the night, I would soooo long for my bed. So much so, that I starrted bringing him to bed with me so that he would fall back asleep.
J and I both loved the night time cuddles that he would give us. The one rule that we put in place, was that he HAS to fall asleep in his own room. If (when) he wakes up, then he can come join us in our room. The odd time we break the rule (if he is sick, or if he had a long afternoon nap and isn't ready for bed yet when we are) but otherwise, we have been able to stick to it.
When Kyle was born, I found that I loved to bring him to our bed, because it was super easy to nurse him while I slept. It was peaceful, and we both got what we needed. The only concern I had with Kyle, was that Julien would kick/squish or hurrt him some other way when he climbed into bed.
Now that Kyle is older, I don't have those same concerns, but he sleeps so well in his crib that I don't want to mess with it.