Benefits of lazy loading
The benefits of lazy loading aren’t just the increase in website loading speeds. Lazy loading comes with additional benefits as well, such as:
Faster website load times
Small websites and assets of small file sizes will load fast. Lazy loading helps to shrink the initial size of a website, which helps it load into the browser faster.
A faster website comes with a lot of benefits. When you lazy load images for your website, you can improve conversions, increase and enrich the user experience, and make the site far more SEO-friendly, which search engines will love.
Reduced bandwidth usage
When your images are lazy loaded, website users will only receive the assets they need. This means that the browser will not need to waste bandwidth downloading images that the user will never see. This can create a nice reduction in bandwidth usage over time.
If your site has a lot of images of larger file sizes, that conservation of bandwidth usage can make a huge difference right off the bat. This conservation of bandwidth benefits both you and the user. Since you’re not serving those assets, you’re also keeping bandwidth usage down for your servers as well.
Improved user experience
Lazy loading improves the user experience in several ways.
No one likes a slow site. In fact, slow sites can often make a user feel as if there’s something wrong with the device they’re viewing the site on.
Faster loading can also improve the user experience in ways that aren't as noticeable. For example, their browsers will not need to do all the heavy lifting of downloading so much in the background. This can save their system’s resources and allow their devices to run better while they’re on your website.
All that activity from the browser also means activity from the CPU, battery, and other device resources. This is one reason why lazy loading is one of the top mobile SEO best practices.
Better SEO performance
Faster page loads are a critical aspect of search engine optimization (SEO). Search engines often penalize slow sites, and one of the biggest culprits of slow site loading comes from images. If you want to boost your site performance and increase your search engine rankings, you need to maximize your loading speed.
Drawbacks of lazy loading
Lazy loading implementations can come in various forms, and not all methods of lazy loading are suitable for all sites.
Sometimes, implementing lazy loading can become a complex task, especially if you’re using a CMS that would prefer one method of implementation over another.
That also means you can run into compatibility issues when attempting to use lazy loading. You may even have a CMS with lazy loading included by default. When you attempt a different type of implementation, it can create more compatibility issues.
Some other drawbacks can come from how the user scrolls your page. If they scroll it very fast, the lazy loading can’t keep up. This can become detrimental to certain types of websites. For example, E-commerce website development wants images that always remain on the page.
Fast scrolling can also create buffering issues. Additionally, lazy loading creates more server calls that can add up if the user continues.
A final potential drawback comes from reduced caching benefits. Caching usually only works when assets are requested. Or, the information in the cache can sit for a long while and become out-of-date or obsolete because of the rarity of its use due to lazy caching.
This may seem like a lot of disadvantages, but for most use cases, the benefits of lazy loading far outweigh the potential drawbacks.
A lot of the drawbacks also have to do with implementation. Lazy loading can work in various ways, so it's important to get it right. The right implementation will give you the best possible results.