Some shops have a "current" table and "archive" table for a given schema so that queries on recent operations are not bogged down by old data. I wonder what people's opinion of this practice is?

One approach is to have a "mirror" database with all the same tables as the current database. Another is to append "archive" to the name of a given tables(s). The first approach generally is cleaner in my opinion. However, a shop may not want to archive everything, only certain tables.