My opinion is they do no harm if they allow you and your baby to get a good night's sleep or a nap.When I was a new mom, it was like a gift from heaven (especially when I couldn't find one at 2am. Which meant a trip in the car for one of us to go get one at the 24 hour superstore, but it was worth it. )

The time when using pacifiers becomes problematic is when you let the child continue to have one for too long and it affects their teeth. According to the Colgate website here, giving a baby a pacifier for the first couple of years is unlikely to cause “significant damage”. It's when they're still lugging it around at 6 you need to worry.

Want to hear a rough rule of thumb which has no scientific basis and is just my humble opinion? Here it is if you like it or not. If they're old enough to say no when you try to take it off them, they're old enough to give it up.

You're welcome, loolarbelle. :)  Yes, I think you're right about thumbs and to my mind, that's one big plus a pacifier or dummy has over the thumb - you can take it away from them.The only thing I've heard anyone do to try prevent thumbsucking is  painting their thumbs with Stop 'n'Grow.

I had to chuckle about your niece because my son was the same! He was extremely adept at hiding them away where no one could find them but him. Many a time I'd be turning the house upside down trying to find one so he'd settle for the night with no luck and the next day he'd be toddling around with one in each hand and one in his mouth from his secret stash. When we were ready to take them off him for good, it took us weeks to whittle down his collection. Every time we thought we'd thrown out the last one he'd appear with another.

I hate seeing older kids with them too, I must admit. If it were me I'd be frightened they'd want to take it to school or something and then would get picked on.