If your website or blog is based on WordPress, then here are some of the best plugins that help you with maintenance.

Broken Link Checker: Checks your blog for broken links. It monitors links in your posts, pages, blogroll and custom fields. It detects missing images and broken links and notifies you on the Dashboard. You can also search and filter links by URL and anchor text.

Maintenance Mode: This plugin will come handy when your web site or blog is under construction or maintenance. It adds a splash page to your blog to let visitors know that the blog is temporarily down for maintenance. Administrators once logged-in, can have full access to the blog including the front-end.

WP-DBManager: Enables you to backup, optimize, restore and repair your WordPress database. It supports scheduled backups. You can even drop/empty tables and run selected queries.

Site Maintenance: This plugin puts your site under maintenance mode by sending a ’503 Service Unavailable’ status to visitors.

WP Security Scan: Scans for security vulnerabilities in your WordPress installation and suggests corrective measures. It checks database security, passwords, file permissions, WordPress admin security and more.

AntiVirus: It’s an effective plugin to protect your blog against spam injections and other exploits. With this plugin you can perform a daily automatic check to make sure your blog is secure. You can do a manual testing and obtain immediate result of the infected files.

Trash Manager:   With the new functionality – Trash introduced in WordPress 2.9 by default you cannot directly delete posts, pages and comments. They have to be moved to Trash first, and then deleted. To make it easier for you, Trash Manager adds ‘Delete Permanently’ link to post, page and comments list. This enables you to delete them directly without having to move them to Trash first.