Imagine a Salesforce flow that is not a record-triggered flow, and you get an Account record.
In the get step, you probably use the default setting “Automatically store all fields”, which is good. Let Salesforce work for you. The record variable is called “Get_Account”.
Now you want to update the Phone field for this record. Should you update “Get_Account” directly or start with a clean record variable?
Let’s first investigate the former approach.
Get_Account hold all the account’s fields. If you set Get_Account.Phone = {new value} and then perform an update on Get_Account, all fields are updated – even the ones you don’t set in the flow. You can see this in the flow’s debug log.
Now let’s investigate the latter approach.
This means creating a new record variable called Account. You set Account.Id = Get_Account.Id and Account.Phone = {new value}. Now when you perform an update on Account, only the phone field is updated.
The takeaway
Using a new record variable instead of the one from the get step is a cleaner and more efficient approach.