Trello: refer checklists
Sometimes we use Trello checklists to define subtasks and it would be nice if we could track time for those subtasks.
I've added your idea into our backlog. It makes sense and we'll discuss how to better handle this.
There's a workaround that I've found shortly after posting the suggestion.
I've defined a checklist with several subtasks inside Trello card and used the following naming convention for everhour entries:
@projectName - Card Name - Subtask Name
Last part of the name ("- Subtask Name") is just subtask name that was copy/pasted from Trello.
This way I was able to track time for each subtask separately and the report was under Reports > Report by Task > Arrange by Project > Aggregate by Comment.
Downside of this approach is that you have to be careful when naming subtasks. For example, if you delete or add a # tag, or if you misspell the name, then each subtask will be treated as a separate comment and the report will contain more than one record for the same subtask.