Your Mac’s mobile data savior.
When TripMode is ON, it prevents all your Mac apps from accessing the Internet but those that have been whitelisted by yourself. It typically stops automatic updates, online backups, Photos syncs, and various obscure apps from consuming precious data. Both uploads and downloads are blocked.
Quite why TripMode’s features aren’t baked into every OS remains a mystery. Until they are, this looks to be an essential bit of kit for anyone who tethers their Mac to a ‘phone.