I've had a fetish for disposable diapers since my mind has thoughts of its own. I like how they look, how they feel, the smell, the crinkle, having a full one on, and the feeling of a new one after having just changed. If I stay some days without wearing, I start dreaming about them, and when I do it's always sexual. It's just a part of me as well as any other side of my personality.
Since I started buying quality brand ones a few years ago, I'm also appreciating the comfort of not having to wake up at night if I need to go #1 or #2. The increased diaper usage has led me to being more sensitive of my bladder status (= even though I can hold it as much as before, I feel I have to go way earlier, and I'm uncomfortable until I can't relieve myself), and this has led me to more wearing. A vicious (or virtuous) circle, or something like that