When I first bought my 3D-printer, I did that mostly because it was fun. There were no thoughts of what I wanted it to be used for. Many of my non-technical friends also said that it was an expensive toy. I can not completely disagree, but after I got the 3D-printer I have used it for a lot of useful prints as well. For instance, I have been 3D-printing GoPro mounts to my motorcycle helmet and other GoPro mounts as well.
When the zipper pull on my motorcycle pants was destroyed, I was thinking how I could fix that myself. Using a paperclip by itself is fine, but it do not look that good. When I did a search on Google, I found a 3D-model that was perfect. A simple 3D-model that fits around the paperclip and looks good as well. The print time was just about 40 minutes and then I had a couple of them.
Installing the zipper pull was just to add the paperclip to the pants zipper and then fit the 3D-model over it. I glued the two 3D-printed parts together as well. For me, getting a 3D-printer has been fun to play around with and also showed me that I do not need to buy all the expensive accessories and that I can easily print a fix to the zipper myself.