Changes in development mode are applied immediately. If you are browsing your website in development mode (using the APSIS bookmarklets), you should, therefore, see your changes directly.
When you deploy a version to live, it can take up to 10 minutes for the changes to be applied to your website. This is because APSIS uses caching for efficient delivery.
If your changes are not applied it can be due to your browser caching the content. Try to clear browsing data and test again.