My 12 week old is starting to extend his time between feeds, too. Generally, he goes 4 hours for his first 2 cycles and then 3 hours for the next two (and I cluster feed 2 hours after the 4th feed before bedtime as he is yet to get in a successful dream feed) - I am just starting to work towards the transition to 4 hours and plan to do so by slowly extending the time in the afternoons between feeds as he is doing it himself in the morning already. I decided to do this when his night wakings continued past his 3 month growth spurt and has needed full feedings at both night wakings....