I still turn mine on for my 1 year old but it's force of habit really. If he's doing anything other than really yelling when he wakes up I usually turn it off again. He usually wakes up at about 7am and chatters to himself for about half an hour and plays with a really annoying teddy bear that plays a tune, I really should break the habit, he's only across the hall!
we still used one for dd till she was about 3 but it was used with the parent unit downstairs as it was hard to hear her if she was upstairs and we were downstairs. We still use one for ds (23 months) but it is for the same reason as for dd. We never used the parent unit upstairs as we can hear them cry out when we are all upstairs.