# The standard zeros > The standard zeros are a handy set of 'buckets' that can store information in the unused space at the top of areas and categories. ## What happened to 00-09? You may be wondering why we started our: - Areas at `10-19` and not `00-09`, - Categories at `11` rather than `10`, - IDs at `.11` rather than `.00` or `.01`. Why don't we use these numbers? ### We reserve them for the system Sometimes you want to keep information _about the system_, in the system. And sometimes you want to keep special things 'at the top' with a consistent number. This is simplest to describe from the bottom-up. This also mirrors how useful I find them: the category-level IDs are more useful than the area-level, which in turn are more useful than the system-level. > **Note:** this is definitely an advanced concept. It's okay to ignore this until you're really comfortable with Johnny.Decimal. And a heads up that some of the figures below use [AC.ID notation](/documentation/acid-notation/). --- # Category-management IDs Within each **category**, the following **IDs** are standard. Use them when you want to manage information or data _specific to the category_. ### .00 JDex If you need to, this reserved ID is where you store category-specific JDex data. For example, you might describe why you designed a category the way you did. ### .01 Inbox A place to store something that you intend to organise soon. When building your system, this can be particularly useful. Design your categories, create inboxes, and as a first step move your existing stuff in to them. You _must_ tidy this up regularly. Don't let anything sit here: you will forget about it. ### .02 Task & project management A place to manage tasks that relate to this category. 'Tasks' in this context means any _thing to be done_. This might be more expansive projects, or you might use it to store checklists for items that repeat. e.g. store a video recording checklist here and run through it before you record a video for your blog. ### .03 Templates A place to store templates that might be used in this category. e.g. in our creative system, we copy the same eight folders to every new job. These empty folders are stored at `50.03`. ### .04 Links A place to store links that relate to this category. I tend not to use my browser bookmarks. Instead, I record interesting links in a note in my JDex. This way I can annotate them with descriptive text, and they're easy to find. This is particularly useful at work with a shared system. e.g. create a shared note that links to all of the places you always log in to, like the timesheet system. ### .05 .06 .07 .08 Reserved for expansion. Do not use. ### .09 Archive A place to store something that you do not intend to organise, but do not want to throw away. This folder might be chaos: that's fine. If there's stuff in here that _should_ be organised, move it to `.01`. ### Name them explicitly Make it obvious what these items relate to. e.g. `11.01 Inbox for category 11`. --- # Area-management categories Within each **area**, the **category** that ends `0` is the area-management category. We name them so that this is explicit. e.g. `10 Management of area 10-19`. This is a less specific place than the category-level IDs we just saw. You should prefer to use those where possible. But if you have something that relates to _the whole area_, use the zeros here. So if you have stuff you want to archive related to `10-19 Life admin`, and you can't decide on a specific category, put it in `10.09 Archive for area 10-19`. --- # System-management area `00-09 System-management area` is the system-management area. ;-) This is less specific again than the area-management categories. You should prefer to use those where possible. In this area, we create a standard category `00 System-management category`. So if you have something you want to store in an inbox but you have no idea which area it relates to, put it in `00.01 Inbox for the system`. ## 00.00 JDex This is a very important location: it holds the system's index/JDex. This is the very first ID. If you were lost, where would you look? You'd start at the beginning. That's how to think about `00.00`. Your JDex might not _be_ here. I keep mine in Bear, which has its own way of handling notes. But you should _tell yourself_, using this JDex entry, where the system's JDex is. And if you do use an app that keeps notes on disk, like Obsidian, then those notes should live here. Also see [the 'single file' JDex method](/documentation/jdex-other-methods/). --- # A map The pattern in area `10-19` repeats for all higher area numbers, and similarly for the categories. ## A decision chart When saving data, you should prefer the most specific zero. Related forum post: [Alternative layout for the standard zeros](https://forum.johnnydecimal.com/t/the-standard-zeros/1558/12).