My DD has always been a sucker and to stop her sucking her wrist not long after birth (she had blisters in utero!) we gave her the dummy.

There are a couple of additional concerns (apart from having to wean them off it at a certain point) at having a dummy-addict, once your child is a toddler:

1. It can inhibit their speech development, because it muffles their sounds anyway, but also stops them forming words correctly with their mouth; and

2. It can stop them learning to bite/chew correctly if it's overused (same thing as no 1)

Because these 2 are only going to occur if the toddler is sucking the dummy often/constantly, I avoided it by only giving her the dummy to sleep. She hands the dummy back to me when she wakes up happily and I put it in her bed for her at nap or bed times.

I never had a problem with her losing the dummy during the night and waking up for it. She doesn't usually sleep sucking it all night but managed to find it herself after a certain age. She doesn't wake up when it drops out, so it might not happen!

I've been told (though haven't tried it), that you can attach the dummy to chain whilst sleeping so they can learn to find it themselves as they are only short chains.
I wouldn't recommend this as a chain (no matter how short) could still be a hazard for a sleeping child). They will learn to find it themselves without the chain.