For me, it started at the age of 12 or 13. Many girls at school had pacifiers attached to their backpacks and they would sometimes even put them in their mouth but mostly for fun, I guess. Still, I felt strange about that and did not really understand why. I also noticed older kids having pacifiers more often at friends' houses. One of my friends seemd to actually still have a paci she's been using regularly. At age 13, I finally got me some NUK pacifiers in size 3 after walking past the pacifier section at the local supermarket many times.
Since then, I have been using them sometimes more often and then again not that much in other times. But I am a very passionate collector and have many old packages still sealed.