We've always had a strong opinion about WordPress plugins - the success of the CMS comes also thanks to the huge variety and availability of different WordPress extensions. Even for Joomla - the success of any site is whether it is able to do more than just it's core function.
WordPress plugins are a huge part of the success that WordPress enjoys.
They can also be a curse. By their very definition, and additional functionality, will come at additional "work" which the server has to do. They WILL make thus make your site slower than a native WordPress installation. You have to minimize WordPress plugins to the barest minimum to make your site faster.
Of course - sometimes you'll need them, but you have to reach a balance between functionality and performance.
Which WordPress plugins should I remove?
We are of a very strong opinion that some WordPress plugins are absolutely essential. If you intend to have an online WordPress shop, you'll have to have an ecommerce plugin. And we also recommend a backup extension.
You'll need to check though which are the absolute essential plugins to your website. Anything which is non-essential should go (or at the very least the plugins which it uses should be completely disabled). Even if your caching has been activated - if you did minimize WordPress plugins, they will still have a performace hit.
Remove WordPress plugins you tested and forgot about
Take a FULL backup before proceeding - the following action is not without risks
Many people try lots of extensions whilst designing their site. Some eventually are used, whilst others are not. If you're like us, you've probably forgotten to remove quite a few of these testing plugins.
Go to Plugins > Installed Plugins. Browse through the extensions you have installed and remove any WordPress plugins which you know you are not using.
Remove or disable inactive WordPress Plugins
Next, you'll want to disable plugins which are not active.
Go to Plugins > Installed Plugins.
You'll see that some of the plugins are inactive. These are of course a no-brainer. You're not using them and they are just a risk.
Remove unused WordPress plugins
If anything is not active and you won't be using it in the near future, Trash it. If there are things which you might not need, you can delete those plugins too. Each plugin has a hit on WordPress performance. You want to reduce those hits as much as possible. Remember that even if caching has been activated - WordPress plugins still have a performace hit. You need to minimize WordPress plugins as much as possible. If it is possible to combine extensions, so much the better.
Browse through the plugins, and try to understand what is the function of each specific plugin. If you think it is not necessary for the functionality for your website - disable it. You need to be a little bit careful and understand what a plugin does before disabling it. Err on the side of caution where you have doubts. However, you should disable unused plugins. Each one of them has a hit on the initial loading time. The plugins are eating away from the initial load time which has the most critical impact on having a fast (or slow) website.
Measure the performance impact of each WordPress plugin
Once you have cleaned what you do not need - you still need to see what performace impact the WordPress plugins you left have on your website. To do this, we're going to use the P3 plugin. The is the Plugin Performance Profiler. It is a bit of a contradiction to install an additional plugin, but this will only be used temporarily.
Download the Plugin Performance Profile here.
Install the plugin and activate it.
Once you've done that you can run a scan of the performance of each plugin.
Now, to see the results of this, you'll need to review the results a little bit in detail. You'll be able to see how much time each plugin is consuming in terms of loading time. Once you do this, you'll know what is causing the largest load time nad whether you need to replace or optimize that specific plugin. Once again we fully recommend you remove WordPress plugins to make your site faster.
If you think there are things which are not bringing enough benefit as opposed to the performance impact, you might consider disabling them or deleting them. The ones highlighted in red are the ones with the worst performance.
Once you have cleaned and minimized WordPress plguins as much as possible, you should see a marked improvement in your website load time.