My DD is approaching 22 months and has a dummy since she was a cpl of weeks old.
I dislike it (personal thing) but she uses it when travelling (we commute to London a few days a week so it helps on busy trains!) and for sleep - she is quite attached to it and asks for it when tired of getting in the buggy.
Anyway she has the tommie yippie 0 - 6 month size (not the teeny tiny newborn size). I haven't got any new ones in ages and have always just replaced like for like in the past. Partly because that was what she was used to and partly because I was hoping she would just stop using it when it got too small lol.
Anyway it has suddenly occurred to me that have a dummy made / branded as for so much a younger age range might be detrimental physically. I can't find any info tho so thought i'd ask the oracle of mums net!