The idea is that before 12 months, your child hasn’t had the time (or the cognitive ability) to form a deep attachment to a pacifier, so taking it away may not be as difficult.
Not the case if you try to wean a toddler off his pacifier. Starting around 18 months, a toddler has strong feelings of attachment to their pacifier. Try to take it away then, and it’ll probably be much harder than if you’d done it earlier. Not impossible, of course, but filled with more tears and anger on the part of your toddler (and maybe on your part, too!) Beyond a few years old and you add the risk of causing dental problems, too.
How To Ditch the Pacifier
Just like there’s no “right age” to ditch the pacifier; there’s no “right way” to do it, either. There are a few things to keep in mind, though, as you create your plan for pacifier weaning:

If you’re weaning a toddler, you might want to be creative. You can just get rid of the pacifiers when your toddler’s not looking, of course, and end things cold-turkey. But you could also be creative, and get your toddler to help with the weaning process. I knew a mom who told her 3 year old son that they needed to send his pacifiers to children who didn’t have any — he helped her pack them into a box and everything! It turned out to be a great solution for that family.
Here is a tip I used in my own home that may help you:

Bribery: Yes, I said it, bribery! My son packed all his pacifiers into a zip lock bag and we took them to the dollar store ( cheaper, and you’ll see why ). I told him he could buy one thing for as many pacifiers he had. He was so excited every time he picked up a toy he wanted and I said “yes” to. By the end of shopping, he had 10 toys/trinkets of his own choice. We went to the register to pay for the items with his bag of binkys ( the cashier was well aware prior to getting up there ). It came to $17! See, much cheaper than buying ten toys from another store! He was the happiest little guy about doing this. At night when he asked for his pacifier at bed time, I gently reminded him that he bought all these “wonderful” new toys in place of them and was more at ease with it. It took a few nights of asking, but eventually he forgot about it.

Be patient. There’s bound to be some fussing and sleeplessness when you finally banish the pacifiers. That’s just how it goes. So prepare yourself to be patient, and to ride out the storm.

Be firm. But that might not be the best approach, especially if you’re weaning a toddler. Why? Because parents, your toddlers are smart. And if they get even the slightest inkling that their actions (crying, screaming, tantrum-throwing, etc.) can make you change course, guess what’s going to happen? The crying, screaming, and tantrum-throwing will only get worse. Better to be firm and consistent now — not only will the pacifier weaning happen faster, but you’ll teach your toddler the valuable lesson that mom and dad mean what they say.