# Saving files

> Learn how to save files to save your sanity. Your new superpower is naming files and/or subfolders by using the date correctly.

## Structure vs. content

Before we start saving things, let's take a quick look at the structure of the
Johnny.Decimal system. Just to reinforce why we put things where we do.

The number before the decimal tells us what area and category we're in. It gives our system its structure. The number after the decimal is the ID. This is where we store our content.

<JDLineDiagram
  text={`
╔═══════════════╦═══════════════╗
║   Structure   ║    Content    ║
╠═══════════════╬═══════════════╣
║    ┌──────┐   ║   ┌────┐      ║
║    │ Area │   ║   │ ID │      ║
║    └───┬──┘   ║   └─┬──┘      ║
║        │      ║     │         ║
║        ┴           ─┴─        ║
║        1 5    .    5 2        ║
║        ─┬─                    ║
║         │     ║               ║
║  ┌──────┴───┐ ║               ║
║  │ Category │ ║               ║
║  └──────────┘ ║               ║
╚═══════════════╩═══════════════╝
`}
  alt="A diagram showing a Johnny.Decimal number, 15.52. Callout boxes label the first 1 as the Area, 15 as the Category, and 52 as the ID. In front of the category is the word STRUCTURE, and beside the ID is the word CONTENT."
  figNumber="62.16A"
  figCaption="Before the decimal is structure, after the decimal is content."
/>

So if we wanted to find folder `15.52` in our filesystem, we can see that:

- It's in area `10-19` because it begins with `1`.

- It's in category `15`.

- And its item number is `.52`.

## Saving files in ID folders

We save our stuff in our Johnny.Decimal ID folders. Spreadsheets, documents, scanned receipts, references, emails, images, and whatever else you're organising.

### We don't save things in areas or categories

We never save things in area or category folders – these are structural only. They're there to guide us to our content.

If you genuinely can't find an ID that feels right, you might need to spend some time expanding your system to include a new category, or even a new area.

<JDLineDiagram
  text={`
10-19 Life admin
│     ❌ Don't save files here
└──── 11 Me & other living things
        │  ❌ Don't save files here
        └──── 11.11 Birth certificate & proof of name
                    ✅ Save files here
`}
  alt="A tree diagram of a folder structure. Directly under the area folder called 10-19 Life admin, there's a warning with a red cross that says Don't save files here. The same warning is under the category folder called 11 Me & other living things. In the ID folder called 11.11 Birth certificate & proof of name, there is a green check mark and text that says Save files here."
  figNumber="62.16B"
  figCaption="Files are saved in IDs, never in areas or categories."
/>

## Saving files in subfolders

I used to be anti-subfolder but I've folded like a cheap suit. There are plenty of cases where it makes sense to use subfolders.

### However

There's no point to any of this if you just go back to putting your stuff in boxes-in-boxes-in-boxes-in-boxes. Stick to one level of subfolders, label them neatly, and don't have too many.

For example, our trip to Japan is quite complex. So we've organised by subfolder.[^travel-template]

[^travel-template]: This is a standard template we're using for any longer work trip. I recommend making templates where relevant. Don't reinvent the wheel every time you do a similar task.

<JDLineDiagram
  text={`
15.55 Japan, 2025
├──── 10 Planning/
├──── 20 Travel documents & visas/
├──── 30 Transport/
├──── 40 Accommodation/
├──── 50 Itineraries & schedules/
└──── 60 Expenses to claim/
`}
  alt="Our Japan trip folder, 15.55. Inside it has the following subfolders: 10 Planning, 20 Travel documents & visas, 30 Transport, 40 Accommodation, 50 Itineraries & schedules, 60 Expenses to claim."
  figNumber="62.16C"
  figCaption="One level of neatly-labeled subfolders in our Japan trip."
/>

If we didn't have subfolders there would be files all over the place. They're helping us find our things quickly, confidently, without stress. So it's all good.

## Sorting by year-month

Let's take this even further. Whether you're naming subfolders or files, if you use the date correctly it solves so many problems.

For example, the ID `15.41 All short trips` from the [Life Admin System](/las/) contains all of our short trips. The sort of thing that you don't really plan, you just book and go.

You can fit a lifetime of short trips in one ID if you create a new subfolder for each trip, and start it with the `yyyy-mm-dd` date.

<JDLineDiagram
  text={`
15.41 All short trips
├──── 2016-10-10 Weekend in Darwin/
├──── 2017-03-01 Drive to the coast/
├──── 2018-02-09 Boat to Tasmania/
├──── 2019-06-13 Drive to Bourke/
├──── 2021-01-01 NYE trip to Googong/
├──── 2023-02-11 Bus trip for birthday/
├──── 2023-09-30 Train to Adelaide/
├──── 2024-02-13 CBR-SYD Weekend in Sydney/
├──── 2024-05-27 Train to Griffith/
├──── 2024-06-18 CBR-LRE Qantas museum/
├──── 2025-04-09 Drive to Narrandera/
└──── 2026-01-07 Hotel in Cobar/
`}
  alt="A tree diagram for the ID called 15.41 All short trips. It shows a dozen subfolders. They all start year-month-date, so they sort neatly. Each is followed by a trip name."
  figNumber="62.16D"
  figCaption="Every subfolder sorts neatly by date when you start with year-month."
/>

Remember, year-month must come first. If you reverse the above dates, the folder would sort like this and be chaos.[^date-format]

[^date-format]: We've used the UK date format, but the US format would still deliver chaos!

<JDLineDiagram
  text={`
15.41 All short trips
├──── 01-01-2021 NYE trip to Googong/
├──── 01-03-2017 Drive to the coast/
├──── 07-01-2026 Hotel in Cobar/
├──── 09-02-2018 Boat to Tasmania/
├──── 09-04-2025 Drive to Narrandera/
├──── 10-10-2016 Weekend in Darwin/
├──── 11-02-2023 Bus trip for birthday/
├──── 13-02-2024 CBR-SYD Weekend in Sydney/
├──── 13-06-2019 Drive to Bourke/
├──── 18-06-2024 CBR-LRE Qantas museum/
├──── 27-05-2024 Train to Griffith/
└──── 30-09-2023 Train to Adelaide/
`}
  alt="A tree diagram for the ID called 15.41 All short trips. It shows the same dozen subfolders. But now they start with the day of the month, so there's no semblance of order."
  figNumber="62.16E"
  figCaption="Oh no!"
/>

### This works for so many things

Purchase receipts is another nice example. You can fit a lifetime of receipts in one ID if they all start with the date, then what it is and where you bought it.

Also consider things like utility bills and finance statements. Don't save them with the gibberish names from the utility company or bank. Using the year-month method, you can store hundreds of neatly-sorted, easy-to-find documents.