Shopify is fast out of the box, which is exactly why a slow Shopify store is so frustrating. The platform handles hosting and the heavy lifting for you, so when a store crawls, the cause is almost always something added on top. And on an ecommerce site, slow is not just annoying, it is lost sales, because every extra second on the way to checkout quietly costs you orders.
The biggest culprit is apps. Every app you install usually injects its own scripts and styles into every page, whether that page uses the app or not. Install a dozen over a year, leave a few you stopped using, and your store is now loading code for features that are not even on screen. The review popup, the currency switcher, the upsell widget, the analytics add-on, each one taxes every page load.
Where the real fixes are
Start by auditing apps honestly. Remove anything you are not actively using, and check whether the remaining ones load their code everywhere or only where needed. Then look at the theme: heavily customised or bloated themes carry a lot of unused weight, and oversized hero images are a classic offender on the homepage, where first impressions are made.
Images deserve their own pass. A store is mostly product photos, and unoptimised images are usually the single heaviest thing on the page. Properly sized and compressed images, served in modern formats, often make the biggest single difference to how fast a store feels.
If you have cut the app bloat, tamed the theme, and your store still drags, that is when custom work earns its keep, trimming the code the store actually ships and tuning the path to checkout. But most of the time the fix is not exotic. It is removing what you piled on and giving the store back the speed Shopify gave you to begin with.