Component or plugins?

Component (Components > Easy Redirects)

• Where you manage rules, the 404 log, import, URL Tester, and Configuration
• Does not redirect visitors by itself

System plugin

• Matches published rules on each public request
• Logs 404s and can render branded 404 mode
• Should stay at ordering -10 (before Page Cache)

Content plugin

• Watches article, category, and menu alias changes
• Creates or updates redirect rules for editors

Simple rule: build behaviour in the component; keep both plugins Enabled for full product behaviour.