Okay, so the title is a bit of a trick question. “Update” is different than “rebuild” in the world of websites. I spoke about that difference a bit in the blog about Building a 21st Century Website. Updating a website is a matter of regular maintenance. If you have a WordPress website, and most companies do these days, I recommend that you check for necessary updates regularly. That’s because updates are released whenever the plugin developer needs to increase the security or fix a bug in the plugin (or WordPress), so regular updates make your site more secure (and less hackable).
As far as how often, I recommend checking for updates monthly. You can always tell if an update is available in the WordPress CMS. But “update” is not the same thing as rebuilding or redesigning your website. Plugin security updates are typically released every month or so, as are updates to WordPress. Technology and usability will typically drive how often you need to redesign a site entirely, but there is a way to tell when your website is at, well, “the point of no return.”
That’s the point at which an update may cause the features on your site – or even the entire site itself – to stop functioning, or to display poorly – or not at all. This can happen for a number of reasons. Some breaks are due to advances in the technology that do not work with older plugins, themes and templates, and that’s not something your developer can control. The plugin developer provides release notes that will help you figure out how extensive an update is. The more extensive the release, the more likely something could break. The fact that there will be times when updating a website may cause more problems than it solves is why I highly recommend that you have your website developer maintain your website.
The older your site is, the more likely you are to encounter issues when it is updated. But that doesn’t mean a brand-new site cannot break with an update. Good website developers know how to build the site and minimize the likelihood that it will break with a typical update, but not all web developers are created equally, and some updates are more extensive than others. Again, I recommend having your web developer make the updates. They know how to do avoid issues; and they know how to fix them when they do arise.
However, if you are going to maintain your own website, before you update anything (plugins or WordPress), back your site up. That way, if something does break when you update it, you can roll it back to the fully functioning version and get your developer to determine why the update caused a problem and what to do about it.
And, in answer to the original question you probably thought I was asking in the title, you should plan to rebuild (or redesign) your website every 3 to 5 years, and sooner if there is a major update (such as an architecture change) to WordPress. Need a good website developer? Email me for referrals.