DD was given a dummy in hosp while they tube fed her to get her to associate sucking with feeding so we didn't have a choice but in saying that I didn't have a problem giving her one.

My nephew is 6 and still sucks his thumb and was never given a dummy.
DD gave up her dummy on her own at 2 1/4 without any issues.

It is easier to take away a dummy than stop thumb sucking.

We talked up the dummy fairy for weeks before DD gave hers up and she decided when she was ready for the fairy to take her dummies and give them to the new babies that were born. It worked well!

We used NUK silicone dummies. She wouldn't have a bar of the rubber cherry shaped ones. One day we left her dummy at home and DH found a different brand in a shop that glowed in the dark! It was great as we were able to spot it in the dark if she woke during the night!