Tracking and Keeping up with 404 errors often overlooked and it is too bad. Keeping up with 404 errors on your wordpress can help with the following items.
- Help users find the information they need
- Help search engines stay up to date
- Improve rankings
- identify potential URL issues on your site
- help keep everything clean and organized
404 and Redirection Plugins
Yoast SEO
https://yoast.com/wordpress/plugins/seo/
I know Yoast SEO can handle the redirections, not sure if Yoast will track and log the 404 Pages
Redirection
This is a redirection specific plugin and it is a great option.
https://redirection.me/
https://wordpress.org/plugins/redirection/
It will do everything you need for redirection, and it is free
404 Error Monitor
https://wordpress.org/plugins/404-error-monitor/
Have not tried this one but the last time it was updated was
Other 404 Plugins
https://wordpress.org/plugins/forty-four/
https://wordpress.org/plugins/seo-redirection/
Reasons you may want to track 404 Pages.
When you convert a website from another CMS to WordPress. If you are familiar with Content management systems you know they all seem to have different URL structures and special page URLs. After you convert, it is a great
Additional Resources
http://www.wpbeginner.com/plugins/how-to-track-404-pages-and-redirect-them-in-wordpress/
https://premium.wpmudev.org/forums/topic/where-is-my-404-error-log-file-in-wordpress

Steven Johnson, a WP Hosting Reviews senior editor, works from Atlanta and covers all things related to WordPress and Hosting.
He graduated from Georgia Tech in Chemical Engineering, has managed hosting companies and now builds WordPress and Joomla Websites for small to medium companies full time.