Product changes and orders are synced immediately, so within moments a change in one store should be available in the other, depending on what syncing options you have in place.
However, changes made in Vend can experience delays depending on how busy Vend's servers are. We've noticed from time-to-time that these delays can be as long as 30 mins, although this is the exception, not the norm. In most cases changes are synced to WooCommerce within moments. If your changes in Vend aren't coming through to your WooCommerce store after 30 minutes, contact us at firstname.lastname@example.org and we'll investigate the issue further to ensure there are no issues specific to your configuration.