If you unblock a previously blocked product then it is necessary to "Upload to Trade Me" or the product will not list on Trade Me.
Editing within Trade Runner
If you want to edit your Trade runner description template, change shipping policies or apply a stock buffer within Trade Runner your products would not update these changes on Trade Me until the product listings roll over on Trade Me which could be up to 8 days, so using "Upload to Trade Me" would be recommended here but not necessary.
Mapping categories within Trade Runner
When you map to a category in Trade Runner, then using the "Upload to Trade Me" button will cause the product to list but you can just leave the mapped product and it should list automatically.
Editing products within your Magento/Woocommerce/Shopify or BigCommerce store
If you make changes to your prices, descriptions, images or other fields within your website then these would not update until your cron runs which depends on your site platform. If you wanted these changes to reflect faster in Trade Me you would need to first hit the "Import from ......." button in Trade Runner, wait for the import to finish then hit the "Upload to Trade Me" button but they will update over time if you leave them.
To see how often your store syncs with Trade Runner please click the relevant link below: