Reusable workflows in SharePoint 2010 are great… but they can be a bit tricky to get started with, as there are several steps required to “update” all instances where a workflow appears.;
If you are using reusable workflows, you have to “Attach” the workflow to a Content Type, “Publish” the workflow, then in the content type “Push the Changes” to the lists inheriting from the content type. This last step is critical – the new workflow will not appear or activate at the list level on trigger events unless it is pushed out.
I spent a good hour or so trying to work out why my workflow changes were not filtering through to the lists they were attached to. Easy mistake to make, as it’s not particularly well-documented 🙂