Haven't had time to read whole thread but here's my twopenneth:
Dummies can give children enormous comfort and security and I think they get a terribe press from a bunch of smug snobs who think they are 'common'. I am the first person to leap on anything for being common or downmarket, so I'm quite happy to say this!
I gave all my babies a dummy. First one because he was very difficult to BF, a poor sleeper, very colicky and stressed, and it helped him (and me) hugely. I think I may have hurled him out of the nearest window otherwise. He gave it up entirely of his own volition aged 11 months.
2nd baby was given a dummy as a newborn, spat it out, never wanted it, never needed it. Fine.
3rd baby given dummy, it became his best friend for almost 5 years and we had to have negotiations on the scale of the UN for him to give it up when he started school. I had a bit of a 'tired post-nursery TV watching/bedtime only' rule from about 3.5yrs onwards but he would still try to sneak it out of the house and 'wear' it proudly in public if he could! He became almost obsessively attached to it from 2 to 4. All our photos of him seem to be of a huge dummy with a small child attached at the rear! Yes, it was annoying, and a bit embarrassing, but like most childish habits, it stopped without too much trauma, when the time was right. I know it probably made me look like a Poundland Scummy Mummy but I knew I wasn't, and at least he wasn't picking his nose and eating it, or playing with his willy all the time, or pulling his hair out!
I watched Spoilt Rotten the other day and was struck by how many pre-schoolers are losing all their teeth to severe decay and one of the main causes was going to bed with a bottle of juice (or even milk) for comfort. A dummy would have stopped this.
Also know loads of middle class mums who have not allowed their children to have dummies. They had much more stressed babies than I did, somehow thumb-sucking seemed much more socially acceptable .Some of them still suck their thumbs in their teens, as it's a much harder habit to break (vile IMHO) and have orthodontic problems as a result.
Also I do not particularly buy the argument that dummy sucking delays speech. Poor, indifferent parenting or underlying SEN/hearing/health issues delayed speech, not dummies. Out of my three, the only one who was a bit slow to speak and struggled with clarity of speech was the one who never had a dummy! The other two, could talk for England from an extremely early age and were highly articulate into the bargain.
Don't worry about it!