How to automatically update a subitem's date when its status changes to something



Introduction

What if a subitem (task) got delayed and you want its date to be adjusted forward or backwards by a number of days? Is that even possible?
The answer?There’s a much better and cleaner way to achieve the same result, without using a Mirror Column at all.
Let’s break it down.


What is an Offset and how do we set it up?

An offset is a specific number which the automation will base the date adjustment on.

Warning Common limitations

  • Mirror Columns are read-only — you cannot update the value directly.
  • They don’t trigger most automations.
  • They cannot be used in many formulas, rollups, or dashboard widgets.
  • They sometimes cause confusion because the value “lives” on another board.
  • If the connection breaks, the mirror breaks with it.
For simple visibility tasks, Mirror Columns are fine.But for anything operational (automations, updates, syncing), they’re usually the wrong tool.


A better alternative: Sync the actual columns (no mirror needed)

Instead of mirroring the value, you can sync the real column from one board to another. This gives you:
  • Real values (not read-only)
  • Full automation support
  • Cleaner, more predictable workflows
  • No confusion about where the data “lives”
This method relies on the Connect Boards feature.


When to use Connected Boards Column instead of Mirror Column

  • You need two boards to stay aligned
  • You want to trigger automations from the value
  • You need clearer control over where data comes from
  • You need to avoid “read-only” issues


How to set up Connected Boards Column (step-by-step)

Here’s the recommended setup to replace a Mirror Column with something much more powerful:

1. Add a Connect Boards column

On Board A, add a Connect Boards column and link it to Board B.

2. Link items

Link each item to its corresponding item on the other board.

3. Create the Sync Automation

Use the CBA built-in automation:
“When item/subitem created, connect it to items/subitems from another board using this connect columns when this column matches another column and sync ALL future changes where column name and type match
This keeps the values aligned at all times — just like Mirror — but editable and automation-friendly.

4. (Optional) Make it two-way

If you want updates to sync in both directions, create a second identical automation on Board B.


Why this works better than Mirror Columns

Here’s the honest truth:
Mirror Columns are perfect if you only need to see something.
But syncing real columns is better when you need to work with something.
With synced columns you get:
  • Editable fields
  • Full automation support
  • No “hidden source” confusion
  • Better performance
  • More advanced workflows
  • Scalability across many boards
This is the method we recommend to all Fantasy Media users — and it consistently solves 99% of Mirror Column issues.

Quick Loom Video Tutorial: https://www.loom.com/share/9aca874cbf8d41469fc61a76bc4cdc27 When Mirror Columns are still useful
Mirror Columns make sense when:
  • You only need visibility, not interaction
  • The value should remain locked and uneditable
  • A board is serving as a “master source of truth”
  • You want simple reporting without sync logic
  • No automations depend on the value
If that’s your case — Mirror Columns are totally fine.


Summary

If Mirror Columns are causing headaches, the “Connect & Sync” method is usually the best alternative:
  • Cleaner setup
  • Editable values
  • More reliable
  • Automation-friendly
  • Works at scale
  • Easier for teams to understand
Most  monday.com  power-users eventually move away from Mirror Columns — and this method is exactly why.


Need help choosing the right structure?

We'd be happy to hop on a call with you to discuss this further and to make sure our solution gives you the exact result you want. Feel free to  book a meeting  with us!