When Mikaela was born, had anyone asked whether or not we'd co-sleep, I would've laughed right out loud. No. Way. We had a bassinet (that she refused to sleep in) and that was as close as she'd come to our bed. She slept well on her own after the first month, and slept through the night at 9 weeks. We didn't need to co-sleep.
When we moved her into her toddler bed at 18 mos, nothing changed. She liked having a 'big girl' bed, and we had no trouble getting her to sleep at night. This was also the time she began having night terrors, which were terrible for ME, but she didn't remember them at all. She'd have one, I'd sit by her bed and talk to her calmly until it passed. She couldn't stand being touched during one of them, and seeing that glassy look in her eyes made me ache so badly for something to STOP it.
She got a twin sized bed when she turned two and things were just peachy until she turned 3. Over the summer, however, she's gotten into the habit of sneaking into our bed at least 4 nights a week.
At first, Sam and I grumbled over the lack of space, the fact that we woke up sweating from the heat her little body put off, and the fact that no matter how many times we put her back in her own bed, she managed to wake up in ours.
However. I learned a lot about my girl from all this. For instance, before this, I didn't know she wakes up smiling and ready to snuggle every morning. I missed her sleepy smiles and sweet hugs every morning for 3 years! Imagine what I would've missed if she hadn't sneaked into our bed!
I also get more sleep when she's with me. If I wake up at 8, and she's still sleeping, I can sleep for a little while too. If I wake up at 8, and she's not with me, I get up to check on her, which invariably wakes her up as well. (and it solves the mini-heart attack I had the other morning, when I woke up at ~10~ and realized she wasn't up yet...)
Know what else? Now that I've become used to those morning smiles and snuggles, I miss them terribly. Mikaela spent last night at her Aunt KK's, and it was everything I could do not to jump up and run over there this morning, just for my snuggles.