Having a fast website is always a goal worth pursuing, and there are many ways to achieve it – from caching plugins and external caching services to CDN networks. These tools can significantly improve your site’s loading times and overall performance.
However, sometimes over-optimising can backfire. If you enable too many optimisation features at once or combine conflicting options, your site may not function properly or display content correctly. This often happens because modern websites are highly dynamic, and certain optimisation techniques can interfere with their behaviour.
To help you avoid common pitfalls, here are some general recommendations to keep your site fast while ensuring it works flawlessly.
Important Note
These guidelines apply broadly to most websites, but your specific setup may differ. Always review your chosen services and test changes thoroughly to find the best configuration for your needs.
General Recommendations
Disable CSS Processing
Modern websites, especially those with many plugins or third-party integrations, generate numerous CSS files. While it may seem logical to minify or combine these files to speed up loading, doing so can actually cause problems.
- Minification: Most reputable developers already provide well-optimised CSS files. Minifying them again is usually unnecessary and can sometimes introduce issues.
- Combining CSS files: Avoid merging all CSS into one large file. Loading multiple smaller files on demand tends to be faster and more reliable because:
- Large combined files take longer to load upfront.
- CSS selectors (classes and IDs) from different files can clash, breaking the design.
Many modern themes and plugins (including Blocksy) implement on-demand asset loading, meaning CSS files only load when needed. Combining all CSS into one file breaks this system and can slow your site down instead of speeding it up.
Remove Unused CSS
Some optimisation plugins offer “Remove Unused CSS”. At first glance, this sounds perfect – removing any CSS not used on a page to reduce load time.
In reality, this process can cause serious issues. Dynamic themes like Blocksy rely on loading CSS only when features are activated or used. Aggressively stripping out CSS risks removing styles still required later, breaking your site’s functionality and layout.
Because many plugins consider this feature experimental, we do not recommend enabling it, as it can lead to unexpected problems.
Selective JS optimisation
Similar rules apply to JavaScript files:
- Avoid minifying or combining multiple scripts into one file, as this can cause conflicts or errors due to scripts needing to load in a specific order or context.
- Deferring and delaying JS loading can improve performance but should be used thoughtfully.
Deferring JavaScript means scripts load after the page’s initial content has rendered, which generally improves perceived speed and is safe in most cases.
Delaying JavaScript postpones script loading until the user interacts with the page (e.g., first mouse movement or tap). This can help, but it may cause issues on some devices, especially mobile, when many third-party scripts are involved.
Use these options carefully, testing thoroughly to ensure they don’t break essential features.
CDN services
CDNs are excellent for improving performance, especially for popular or high-traffic websites. They deliver content faster by caching it closer to your visitors.
The main advice when using a CDN is to clear its cache thoroughly whenever you make major updates to your site, to ensure visitors always get the latest content.
Multiple caching solutions used at the same time
Running more than one caching or optimisation plugin/service simultaneously is a common cause of conflicts and site breakage. Choose one reliable solution that fits your needs and stick with it to avoid overlapping processes that can cause unpredictable behaviour.
Following these recommendations will help you maintain a fast, reliable, and well-functioning website without sacrificing the dynamic features your visitors expect. Always test optimisation changes on a staging environment if possible, and monitor your site carefully after adjustments.