DS1 was about 17.5months old when we began day sleeps in a kids single bed (decided not to do the toddler one), did that for about 2weeks then started nights too- which would've been by 18months...which he transitioned quite well- i think him having chose his themed bed and putting rails up (which really enclosed it alot) helped. The reason was because we were expecting another baby so wanted to have DS1 adjusted to the new bed by the time DS2 arrived (DS1 was 20months by then).

For DS2 I'd like to try keeping him in the cot til at least 2- only to give us enough time to work out our next plan...like whether to have another baby, then that would determine what type of bed to get and where DS1 and DS2 will go. Because if we do decide to have 3rd child (which i'd prefer wait til after DS2 is 2) DS1's room could end up with a bunk beds and the cot would remain in DS2's current room. Hmm...will have wait and see what'll happen there.