We tried co-sleeping/bedside sleeping in cot very early on with ds, but it was awful. We all slept abysmally. I wanted to bf for as long as poss, except my boobs are the size of fried eggs (and were even while bf-ing), so I couldn't just sleepily flop a boob out in the night; I had to sit up, hoik up ds into position etc, which was pretty disturbing for all of us. And ds made such a racket and fidgeted! And a 4'6" bed isn't big enough for two, let alone three! So ds went into his own room - which was through a door off our room, which we kept wide open - at just two weeks . And I'd pop through to him for feeds in a more practical chair.
Ds is now 26 months, and since we moved house in May, we've co-slept! (All back to front .) It's evolved from me laying on sofa cushions beside ds, to having a whole double bed next to his bed. I still sleep in with him, and love it (as does he), although dp sleeps in our new six-foot bed in our room, which I've barely touched!
Dp and I are fine about not sleeping together, as we're not the snuggle-up-all-night type; we overheat and wiggle about too much. So we figured, if it's sleep we're after, being in separate rooms for a while is fine. What works quite well about me sleeping in with ds, in his room (we're lucky to have the space), is that mine and dp's bedroom is still our room and we can get intimate in there (and elsewhere! ) earlier in the evening, as we have always done.
If we have another child, I will aim to co-sleep from the start - and most probably in a bed in their eventual bedroom again. I could fidget and faff about to get comfortable for feeds without waking dp. And like ds, little one would never have to move out as such, into an unfamiliar space; you just gradually withdraw from their room when they're ready. It's just beginning to happen with ds.
Wish I'd cracked co-sleeping from the start with ds, but I figure - like many posters say - that there is no right or wrong way; you do whatever works for you at the time.