I coslept w/my son (17 months) and am expecting #2 in Jan. I don't PLAN to cosleep (but hey I didn't last time either). We moved my son to his own room at 9.5 months when we became fearful he'd crawl out of the bed in the night! It was a hard transition. He was also always nursed to sleep. I didn't know NOT to do this after a certain time. Then, he became so attached to that as a sleep association that it was hard to break.
I think you do what you have to to survive. We coslept out of sheer desperation, and I loved the closeness to my son (I'd usually end up reverse "spooning" him kind of), yet I was kind of relieved to have my space in my own bed back. My husband did not wake up at a mere twitch, but I did, which also ultimately affected our sleep. My husband's snoring also became a problem. I think the biggest strain was that we had to go to bed when the baby did! That was what I liked most when we got him in his own room. We did it in stages. First at 7 months, we moved the crib to our room. We put him to sleep first in it. Then, when he woke up, he'd still come to our bed. Then, we moved him to the end of our bed. Same, when he woke, he came to our bed. Last, we moved his crib to his room and he went to sleep there and came to our room when he woke. Our son didn't sleep all night until 15 months, which is rare, but after 10 months, there was no more mommy's bed. I had him sleeping on my chest all night b/c he wouldn't sleep and I remember putting him in his crib at 4:45 am and saying this is it! A video monitor let me know he was ok if and when I was finally ready for him to cry it out a little at 10.5 mo.
Basically, I don't want to make the same mistakes this time as last! It was hard to break those habits. Plus, I often wonder if it was our fault he didn't sleep all night for so long.
Email me if you need more help/advice!
R.