First-pass PDF compression: test the most fragile page

Before compressing a long PDF, choose a harmless or approved page with small print, fine lines, and an image. Compress that sample and compare it with the source at normal viewing size and at zoom. Check whether text remains selectable and whether any links or form fields survive. Record the size reduction. If readability suffers, adjust the method before processing the full document. Keep the original untouched; a small successful test still requires a final review of the actual output.