The optimal number of publications can vary depending on specific requirements. However, for categorized or high-quality publications, producing two well-crafted papers is generally considered ideal as per my views.

This cannot be said in general. In humanities, an author can spend several years in writing a book of fundamental value. In sciences with large collaborations (e.g., high-energy physics), the papers have rather often dozens,hundreds or even thousands of authors, and thus each co-author can have dozens of papers per year to which he really contributed.