Hello again,
When I archive a significant amount of data (for example 1 year of SD billing documents), I then let the Basis team know which tables were the most impacted and then they rebuild the relevant indexes. Table/tablespace reorgs are not as common and to my knowledge only done if you need to actually reduce the database size (as opposed to just freeing up space).
Are you familiar with the document "Performance Aspects of Data Archiving"? This can be found out on the ILM Service Marketplace page under Data Archiving -> Media Library -> Literature & Brochures. It contains a lot of good information on this topic.
Best Regards,
Karin Tillotson