Changing WordPress themes is a technically very simple action, just find the new one, optionally preview it and activate the new theme.
Why would your content or the functionality of installed plugins be affected, right?

Table of Contents
Don’t change the theme too often
It is good to propose a change of theme from time to time, for several reasons:
- To offer a new corporate face.
- To adapt the design to new trends.
- To improve image and functionalities.
- To avoid the invisibility that is generated when there are no changes.
- Resource optimization.
But it is such a relevant change, both for the image of your web and for the possible implications it may have. It is convenient to take some time, make thorough tests and even take advantage of the change to make some promotion.
You will decide how often to change the theme, 1 year, 3 years, 6 months? But never overlook to make all the necessary checks.
Make a detailed list of the steps to follow

If there is something fundamental when making a web migration or a theme change, even when changing an important plugin, is to make a list of steps to follow(checking settings, what do we get, what do we lose, things to be careful in the process…) to have the least amount of problems in the process.
Do not leave anything to chance, or trust that “you’ve been doing it for years“, write down all the important steps and check that you do not miss any.
ALWAYS have a testing installation

Both to choose the theme and to check its appearance, learn about its settings and options, and above all to check that everything will work, the first step I recommend is not to do things in a rough way, activating the new theme on your active website, but testing first on a site for that purpose only.
Export all your pages and some posts (20 at least) from your current website, create a WordPress installation with the same plugins and current theme, configured exactly the same and install and test the themes you have in your list of possible ones, or your custom theme.
Don’t forget to add the menus, widgets and even the logo and other visual resources, to check if there are any noticeable differences when changing themes.
By the way, as usual, take the opportunity to incorporate design improvements.
If your hosting offers tools such as a testing environment much better, because then you can dump the new design to the real web when you finish making changes.
Measure optimization and SEO before and after changing themes

This step is absolutely vital and essential whenever you change your theme.
You must measure the SEO and optimization results of your homepages before and after the theme change, using the tools you are used to.
My advice is to at least analyze the following:
- PageSpeeds Insights of your main pages (homepage, services, products, blog, etc.), taking screenshots or printing the results to compare the pre and post results and be able to assess if the change has affected in any way the optimization of the user experience of your visitors.
- Google Analytics – Report before and after the change, in case the theme change has caused any change in the navigation, visualization, retention, etc. in the top 10 pages of your website (those with more traffic).
- Google Search Console
- Coverage report, comparing pre and post crawl errors.
- Discover report of top pages before and after
- Top queries report before and after
These reports will help you identify potential problems or pleasant surprises after the theme change, and take action if necessary.
Make a note of the most important measurements and results in your to-do list for later comparison.
Review Schema markup

It is becoming more and more common for themes to incorporate Schema markup in their code for all types of content (posts, pages, products, etc.) and these may sometimes interfere with the Schema markup you already have configured with the previous theme or through SEO plugins, which also adds Schema markup.
Check what Schema markup the new theme adds if it does, and even if they can be disabled, you will avoid problems indexing rich results in SERPs.
The way to check this is to analyze your different types of content with Google’s rich results test, both with the current theme and the new one.
Check scripts and tags

Something that happens a lot when changing the theme is that, suddenly, the web stops showing statistics, or the tracking is not registered, advertising or social media campaigns stop working.
This is because more times than you can imagine we forget to move from the previous theme to the new one all those scripts and tags that connect our website with external analytics, ads, advertising, etc. services.
So check twice or more times what scripts or tags you have on your website to add them also when changing theme.
Some common ones are …
- Google Analytics
- Google Search Console verification HTML
- Google Tag Manager scripts
- Facebook or other pixels
- Pinterest verification files
- Hotjar or Clarity scripts
- Advertising tags
And the most common ways to add them, which you should check all of them, are usually:
- Script and code management plugins – Best when migrating, because the plugin doesn’t lose settings by switching themes.
- Theme
functions.php
file – Check the theme and its child theme, in case you included there scripts, tags, pixels, etc. - Theme
header.php
file – Scripts such as Google Tag Manager require a code in the header and another in another file, as well as ad platforms and others. - Theme
footer.php
file – Common place for analytics scripts and the like.
Keep all these codes safe, noting where each one should go, and then move them to the corresponding file in the new theme.
Don’t forget menus and widgets

It is very common to forget about menus and widgets when changing themes, without realizing that when you change themes, the theme loads its own menus and widgets, and sometimes deletes forever the previous ones.
Save the settings of your menus and widgets, copy custom codes to a text file, whatever it takes, so that after switching themes you can restore your menus and widgets to their original state.
You can use plugins like Widget Exporter to export, save and, if necessary, import your widgets again.
Choose the new theme wisely

Isn’t it easy to say…
But it’s easier said than done. There is nothing more difficult than choosing a new theme for your website, there are dozens of elements that attract and distract you and that will complicate your task, and you will almost never be 100% satisfied.
My first advice is not to get overwhelmed, if after the theme change you are not completely satisfied, write down what you are missing and keep it in mind for when you plan the new theme change, and get to announce your new design and enjoy it.
Of course, there are some aspects that you should always keep in mind when choosing a new theme, I suggest you check at least these:
- Lightweight and optimized – A good theme will generate only the essential HTTP headers, will load only the necessary fonts, will have the right code and styles and will only load what each page and content type needs. In addition, a good theme will apply the WordPress programming standards. You can help yourself with the Theme Check plugin, which checks that the themes you specify apply the correct and most up-to-date standards.
- Optimized for SEO – Check that the HTML markup of the new theme generates the correct tags (H1, H2, metas, etc.) for a proper SEO hierarchy, which at least does not destroy, but even improves the SEO of your website.
- Don’t include plugin functionality – More and more themes are adding functionality that should normally be incorporated via plugins. Don’t be tempted to choose a theme that will save you from having to install 10 plugins. It is a bad decision for many reasons, but the main ones are that:
- They overload the code generated on each page.
- They will almost never do better than specialized plugins.
- If you change theme a plugin will always continue to work, not a feature included in the theme.
- Compatible with all the major design engines – It is now a must that the theme you choose is compatible with all the major design engines, namely:
- (Extra) Compatible with FSE – If possible, but not essential, that the new theme is compatible with the new functionality incorporated in WordPress 5.9 of full site editing, or FSE, so you can start learning how to customize your website to the new WordPress style. However, this is optional, especially until the full site editing is no longer in beta.
Check everything 10 times, or better 100 times.
Even if you keep a list of the changes, steps and tasks, review everything a few times so you don’t leave anything important undone, but above all stay vigilant the days following the change to analyze if the new design positively or negatively affects navigation, traffic, interaction, dwell times, internal linking, recurring visits, etc. on your website.