# Expand an area: Guidelines
> Guidelines for expanding one area of a Johnny.Decimal system – mix and match the rules and principles to suit the situation.
## A common objection
People see this and say, "well what's the point of Johnny.Decimal if I can just make up my own thing?". To which I say: there are no absolutes in life.
I'm trying to be pragmatic and honest. My default system is great for many things, not _every_ thing. We can still use the principles of Johnny.Decimal to stay organised – these are outlined below.
## Consistency is critical
You can build almost any 'shape' of system and be organised. The key is to _be consistent_ in your structure and file naming. This sounds obvious, but if it's front of mind you won't go far wrong.
Help your future self by documenting your scheme and design decisions in your JDex. The standard zero `00.00 Index` would be a good place.
## Rules
### Only expand the part that needs to be expanded
Aim to expand _a single area_ of your system.
Most of what you do should still fit in the standard Johnny.Decimal structure. If you're a freelance designer, manage the rest of your business with standard areas and categories.
### All IDs start with the area number
Standard Johnny.Decimal IDs start with the number of the area they're in: `83.66` belongs to area `80-89`.
You must retain this pattern. You're going to expand one area. Choose that area, and then ensure that every number that it contains starts with the area number.
#### Example
In the [Small Business System](/sbs/), area `50-59` is expanded and uses a five-digit non-standard numbering scheme: `A0000 … A9999`. `A` indicates the area that has been expanded.
In this example, the usable numbers are `50000 … 59999`. Expanding `70-79` the range would be `70000 … 79999`.
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# Principles
## Use the alphabet
In a standard Johnny.Decimal system, numbers replace the alphabet as the primary sort. This is because most things do not benefit from being sorted alphabetically.
But some things do. For example, if you have a long list of organisations, ordering them alphabetically makes sense.
It makes no sense to allocate the organisations a number and sort numerically. See figure 62.27A below.
## Use the date
Many things benefit from being ordered chronologically: jobs for a client; semesters at university.
And we tend to remember where these kind of things happened 'in time'. So the date can help us find things later.
Look for opportunities to use the date. This must always be specified as year-month-day in the format `yyyy-mm-dd`, e.g. `2024-08-30`. This will sort chronologically in your filesystem.[^iso8601] See figure 62.27A below.
[^iso8601]: This is [ISO 8601](https://en.wikipedia.org/wiki/ISO_8601) for the date nerds.
## Stop using numbers
In a standard Johnny.Decimal system, every item has a number: the ID. However in many expand-an-area scenarios, numbers might only make sense at the higher levels.
Use numbers to guide you to the place you need to be. Or where there isn't an alphabet or date alternative.
But when they become a burden, or when the alphabet or date is better, stop using them. See figure 62.27A below.
## Use natural hierarchies
If natural hierarchies exist, use them. Why invent another scheme for something that already has one?
### Example: A freelancer
A freelance designer organises their workload by client, product, then job. Use this hierarchy in your system (or adapt it to your own situation). Don't worry that it breaks the area → category → ID structure. See figure 62.27A below.
## Look for patterns
A sub-principle of 'be consistent': always look for patterns. If you do something over and over it should be a template. This saves time and helps your brain.
Templates usually benefit from having numbers to keep them in order. Numbering in tens (10, 20, 30) makes sense here. It leaves room between items (05, 15, 25) for one-offs or items you forgot.
### Example: A freelancer
A freelance designer creates promotional material for the footwear industry. They have two clients, Joe's Shoes and Tammy's Trainers. Joe makes three products: Big Boots, Cool Kicks, and Sick Sneakers.
The jobs follow a similar pattern. The client provides a brief, copy, images,
and video. The designer produces working files for review and a final
delivered product.
This is an opportunity to make a reusable template. And to use numbers again.
Not as a unique identifier, but to control the order of filesystem folders.
Here's how their system might look. Area `10-19` is a standard Johnny.Decimal area, and they've expanded `20-29` to handle their clients and jobs.
## Invent your own scheme
There's a reason people love their Johnny.Decimal IDs. They're a useful shortcut in many situations. So if you need an ID for something, feel free to make one up. Just remember: be consistent.
### Example: A freelancer
I like to give each of my invoices a unique ID that relates to the job.
In the example above, we might invent a scheme like `20.JOE.BB.20240708`. We're not going to use this code every day. But it serves as an unambiguous reference to that job when we need one.
And I shouldn't have to explain this scheme: it's obvious to which job I'm referring. Annotate your filesystem and JDex to make the scheme self-documenting.
## Use existing codes
Much of life already uses the concept of a short code. University courses have them. Creative agencies use them. Almost every professional job management system will allocate a 'job number' of some kind. So where a code exists, don't invent another.
### Example: A student
Our student attends university in the Northern Hemisphere. They use the standard [Life Admin System](/las/) at `10-19`.
And they have a similar structure at `20-29` to handle the administration of being a student: finances, accommodation, and extra-curricular clubs. These are standard Johnny.Decimal areas.
Their courses require an expand-an-area solution. They naturally group by
year then semester, and each has a code assigned by the university. Within
each course, we use the same template, numbered from `10 … 60`.
It's convenient that the first semester, Autumn, sorts before Spring. If this
wasn't the case, we could add numbers to the front to force a sort. Perhaps
the month?