Hi,
I use a lot of custom fields in MC and some of them are calculated using very long expressions.
For these fields, I prefer them to be "user-defined" and copy/paste my expressions in the tag editor to avoid long delay in views.
To simplify this, a new option for calculated fields could be useful. The user could specify the update method (for example: "Update when displayed" VS "Update on demand").
For calculted fields with "Update on demand" enabled, an update button could be added in the tag editor.
See my attached image for an example: I use the custom field [Album DR] to calculate the DR of an album, based on an expression which I prefer to copy/paste to avoid slowing down views. It would be nice to define this field as calculated and use a little refresh button to update it on demand. And please don't judge me for having too much ABBA in my library
I don't know if it is feasible or not, but I think it would give a lot more flexibility for custom fields
Best regards,