I think there is a line between addiction and enjoying something.
If it gets to the point that you cannot control it than it becomes an addiction, but just because it makes you're happy and you do it all the time doesn't make it an addiction.
If you have control over it, it isn't an addiction, if you wear 24/7 and can take it off whenever and not wear them for a couple days, than its not an addiction.
People say I'm addicted to the internet and computers, but in reality, I can hop off it, and go out and do things, I just prefer it because it makes me happy, and its more entertaining than lets say playing soccer.
I hate when people slap the word addicted onto things I enjoy, I sometimes game 8-14 hours straight when I have nothing to do and I'm bored, however I can go out, function like a normal adult, and it doesn't effect me any more than that, infact I can go months without touching a computer, but it gets boring as I'm not the social type.
That being said, anything can be addictive, however just enjoying something and doing it often doesn't make you addicted, lets use gambling or drugs as an example, when it gets to the point that you have to do drugs just to function, or have to gamble every couple hours, and not come home for days, if it becomes obsessive and effects you than it is a addiction.
For example, I constantly have to check to see if my door is locked, you can say I'm addicted to checking to see if my door is locked, that effects me, I always have to make sure the door is locked, or I always have to know where the bathroom is, that is obsessive behavior, when it comes to diapers, it could be, you always have to have diapers around, or you need to be around shops to buy diapers, or you plan your day around diapers and avoid specific things because you need diapers etc (unless you're incontinent).
Now, with some people, it is just as an addiction as gambling, just like drugs and everything else, anything can be addictive if you have an addictive personality, I'm addicted to coffee and I literally cannot function without it.
I could not go without coffee for one day, that is when it becomes an addiction.
But the thing is, even if you're addicted to diapers, nothing wrong with that, its not that harmful, unless of course, you're sitting in the same diaper for 7 weeks, and not leaving your room, ahaha, than you could have a entire civilization grow in your diaper. jokes aside.
However that being said, I could be wrong, but I wouldn't class anything as addictive unless it effects you in some way, like I mentioned before, one example would be spending all your money on diapers etc.
I haven't had much sleep in the last three days, so if anything seems out of place that is why
I Know this topic is quite complicated to talk about and I'm no expert, but its very complicated.
I hope I make some sense.