Toddler regression?

My 2.5 year old son all of a sudden HAS to have a pacifier. He only ever used one when he was in the NICU and stopped taking it after he came home. Now he has to have his "kinky" at all times. Is this a normal regression? I still have pacifiers because his younger brother just weened himself off of them not to long ago and baby number 3 is arriving in July. Plus they use them for imaginative play... their dolls and dinosaurs use them. Not sure if anyone has any advice for me? Or do I just let it work itself out?