How often to update WordPress plugins, themes, and core software?

You should update WordPress core, themes, and plugins as soon as updates are released.

How often WordPress updates?

WordPress checks for updates every 12 hours (related: How often does WordPress check for updates?), however, updates are not released on a regular schedule.

My advice is to install a great security plugin like Wordfence, which will email you every time there is an update available.

Related: How to Secure your WordPress website (using Wordfence).