Well, it wasn't something that I had planned yo do, but we did. DD seemed to have a strong need to suckle beyond BFing. In fact, at times she would go to the nreast to just suckle and get so mad when she'd get a mouthful of milk that she would just scream and scream. I would try to give her a pinkie first, and sometimes that would work.
She also HATED her car seat though-I mean she would scream at the top of her lungs from the second she was put in it (and she was a shockingly loud baby-even our FP commented on her astounding volume at her 10 day appoinment). Going to the grocery store 10 min away was a nightmare. Even with 2-3 stops on the way there and back to try to nurse/soothe her would do nothing. Anyway, when DD was 5 weeks old DH had to be out of town for business for several days. I was still anemic and tired from all of my postpartum complications, so I went to stay with my parents. They live about an hour away by car. The ride was excruciating. When it was time to go back home, my Mom suggested that I try a pacifier. I was resistent, but within a few blocks I broke down. DD used her pacifier until she was about 20 mos. old. It went from fairly frequent "need to suck but noy nurse" use to just car & crib, to just crib, to nothing.
In our case, it didn't interfere with nursing and DD self-weaned when she was around 2.5 years. I'm hoping not to need one with this baby, because every child is different and my life circumstances are different. DD was/is just very sensitive to environmental stimuli and quite difficult to soothe. I also had to commute with her (alone) for about 3 hrs. round trip M-F from when she was 6mo.- 18mo. As much as she hated the carseat, I literally can't imagine what a mess we both would have been without something to soothe her-she would never suck on her fingers/thumb, even if I tried to encourage it.
Bottom line, my view with all things parenting is know your general preferences/views but don't try to make too many hard and fast decisions in advance. You never know what your child's needs might be, and you don't need the guilt of feeling like you're "too weak" or something when you decide to do something that deviates from what you had planned.