Workflow Tables

I had some questions about workflow logs and agent determination tables:

What is the typical setup in SAP systems for the tracking of work item approval history and for the agent determination routing? The way I see it is to use the standard approval log table (SWWWIHEAD) and to have a custom table for agent determination.

Would you ever have a custom workflow log table? Is that even possible?

Inversely, is there a standard way to route agent determination without a custom table in the system?

What are the advantages / disadvantages of standard vs. custom for workflow table?

Any help would be appreciated, thanks.