Don't know if anyone uses InkFrog anymore but they have announced a way to automatically end GTC listings up to 1 day ahead.
https://www.inkfrog.com/blog/manage-your-good-til-cancelled-listings-with-inkfrog/
Goes to show how easy this type of automation is to implement!
This also means sellers that use InkFrog are used to 30-days from eBay and are now being offered at best 29-days.
This is less than 96% of the service that sellers are used to with less flexibility. Woot.
