DS was in our room in a cot till about 6 months, then into his own room.
It worked fine at first but around 6 months he started to get disturbed by our noises when we'd come to bed, especially my DH who would often work late and then come in and read for a while in bed around 2am or so.
But due to travel he's been in our room for several months at a time since then. Now he's nearing 4 and will often come into our bed for a bit at night.