To eat your own dog food.
It’s the practice of using your own product, for purposes ranging from testing to promotion. It makes you actually experience the end user’s viewpoint, as opposed to just theorizing about it and having basic testing be done. I feel like it’s a great practice, especially for the hobbyist looking for project ideas: make something you can use yourself!
Sadly sometimes it’s very obvious that the product hasn’t seen any real use during the development phase. Very simple example, I have a tin of mints sitting on my desk here. It’s a small one, slightly rounded in shape. There’s roughly four millimeters of surface area on the bottom lid for you to grip when you’re opening it. You don’t need me to tell you that’s very little, and I actually required a screwdriver to get it to open for the first time.
Sometimes it’s hard seeing through the eyes of your users. Sometimes you just need to make an attempt.