# What is an ID? > A fundamental Johnny.Decimal question: what is an ID, and how much should it contain? [On the forum](https://forum.johnnydecimal.com/t/quick-start-life-admin-support-topic/1660/20), user **cobblepot** raises the question of how much a Johnny.Decimal ID should contain, and whether it should contain subfolders, and if so how many. My thinking on this has changed _significantly_ over the years. The site needs a proper refresh, which will take time. It's next on my list. Until then, this short video hopefully clarifies my thinking, and answers some of cobblepot's questions directly.