Caveats
The Algolia Search for Magento 1 extension is no longer supported (and Magento 1 has reached end of life). However, Algolia does offer a supported extension for Magento Open Source and Adobe Commerce.
Magento hooks
The extension is using the default hooks of Magento. If you are doing insertion or deletion of products outside of the Magento code/interface, the extension won’t see it and your Algolia index will be out of sync. The best way to avoid that is to use Magento’s methods. If this is not possible you still have the possibility to call the extension indexing methods manually as soon you as do the update.