There are a couple of key factors that can influence the time it takes to re-index changes to your Magento data:
- how often you re-index to Algolia,
- the number of items you are indexing.
Generally speaking, if you use the SKU re-indexing form those items will be indexed quickly. However, if you send a large number of changes to Algolia, those changes will take time to build. We are unable to tell you exactly how long this will take and there is no guaranteed ETA.
To help with indexing speed, make sure that the indexing queue, if you are using this, is configured to update at the correct rate required for your use case.