Backup custom table

No it does not, it will only export all of your posts, pages, comments, custom fields, terms, navigation menus, and custom posts. https://codex.wordpress.org/Tools_Export_Screen

Managing Backups: Space Issues [closed]

You can use a plugin like backwpup that lets you: Store backup to Folder Store backup to FTP Server Store backup to Amazon S3 Store backup to Google Storage Store backup to Microsoft Azure (Blob) Store backup to RackSpaceCloud Store backup to DropBox (free) Store backup to SugarSync (free) and manage the number of backup … Read more

Updating to new 3.0.5

Updating is always important. They contain security fixes and other bug fixes. Generally update within the 3.0x considered safe. Moving between 3.x could require some changes and updates to your theme or plugins. I like to take the mantra, better safe than sorry. I would back up your database and anything your wp-content folder (plugins, … Read more