Parents and children often have a lot in common, but they also have differences which make them unique. The child inherits traits of the parent, but they have their own life experiences and changes which effect how they ultimately turn out. The relationship between WordPress Themes and WordPress Child Themes is actually remarkably similar in this regard. A child theme is a theme for WordPress that has inherited functionality from another theme, which we’ll refer to as the parent. Child themes are tweaked, customized, and latered according to the needs of the user and the preferences of the audience.
The trick to using a child theme correctly is to make just enough changes to make it look unique, but to retain the parental traits that will make it easy to upgrade whenever a new version is released for the parent theme. Upgrading a theme in the past meant losing all of your customization and having to start over from scratch. While you may wonder why anyone would even bother with an upgrade if that’s the case, remember that the web is a place of structural security; if an exploit is found within a parent theme, it will effect the child theme as well. If you don’t update your theme accordingly, it will make your site less secure.
Not all child themes are inherently good, either. The parent theme needs to have enough functionality to warrant customization, or even to allow for it. If the parent theme does not have enough functionality and available features to make customization as free as you would prefer, it would not be the ideal candidate to turn into a child theme for your site. There are actually parent themes that are perfect for this use, known as “theme frameworks.” They tend to provide the greatest range of functionality, sometimes much more than anyone would ever need, with the intent of covering all the bases of a child theme user.
The answer usually comes down to how much time you want to spend in development of your site. If you want to just put it up and pay minimal attention to customization, then a parent theme will usually work well for you. If you plan to use that site for the long term, or want to have a more individual presence, then a child theme is the best way to do so.
Child themes are quick and easy to set up in most cases, almost as much so as parent themes. This depends on the amount of time that you plan to spend in development and how many features you want to tweak, of course, but it’s a very smart way to get your site customized without having to start over from scratch. Child themes are ideal for those who want to add new levels of functionality to a theme. Essentially, the more that you plan to customize your site, the more you should be leaning toward using a child theme over a customized CSS plugin.