I think babies are just designed to take some time to get the hang of sleeping solo. When you are limited by language and still learning about the world, going to sleep on your own, by yourself I think can be a freaky experience for them. Routines that we have now have been able to help some babies to sleep sooner, but I think it's something that if left naturally, will happen successfully. Two years seems to be a big milestone with lots of babies I know going into their own beds successfully, sleeping through a majority of the time etc... but each child is an individual and I think it shouldn't really be measured as 'success', iykwim? I think it's a natural process that takes time (unless you find routines work well for your family). I have to say I am pretty bloody buggered with four years of not sleeping through having had two children, but I know Elijah is 18 months and it wont be long. Then all that hard work will be well rewarded and will feel like a brilliant acheivement for me - letting them adjust in their own time. We have tried routines and all sorts of thing, and this is what worked for us.