Just like how there are hundreds of themes in Shopify, there is a huge selection of apps that offer custom functionality not provided by Shopify or your selected theme out of the box. Coming from Turbify, you will find that while this large selection of custom apps may feel like a blessing at first, you will have to rely on these apps even for mundane things we take for granted in Turbify, such as quantity discount pricing, custom options, or option price markups. On top of that, with few exceptions, apps come with a recurring monthly fee that is usually moderate, but those fees can add up quickly.
While some less complicated apps can be set up quickly, others can be fairly complex to configure and customize, so evaluating apps and learning their ins and outs can, and often will, take time.
For apps that involve individual products in the store, such as product options or quantity discounts, another important consideration is whether they offer a way to bulk upload data. If you are migrating an entire store with hundreds or thousands of products, configuring per-product settings manually is simply not an option. Preparing upload files for custom apps requires following the app's exact upload format, and this process almost always requires a custom solution to translate the store's catalog data into that format.
Apps can be installed or uninstalled from stores at will. They typically come with a grace period and several pricing tiers. In most cases, lower tiers are not suitable for production because of feature and volume limitations.
If you have questions or issues with a particular app, there is always a way to contact the developer's support team. If an app almost, but not quite, provides exactly what you need, some developers are willing to make custom changes, while others are less flexible and follow more of a take it or leave it approach. In many cases we can tweak apps via CSS and JavaScript to compensate for imperfect appearance or missing features, but this approach carries some risk. If the developer updates the app, those updates can break custom tweaks, which may require additional work to restore.