NetGateStart with the apps you actually need.
Open the main panel and look at the applications using your connection. Leave your browser, messaging or call app allowed, then block the background syncs and updates you do not need right now. Every app has its own access switch; the traffic figures help you see which ones have been busy.
Save those choices in a separate profile. A profile keeps independent app rules, including whether newly detected apps begin allowed or blocked. Monitoring is free; changing connection access needs a license and the macOS network extension.
Let the connection choose its rules.
Assign the profile to a connection type, or enable recognition for a saved Wi-Fi network. macOS asks for location permission before NetGate can read Wi-Fi names. Names stay on your Mac; NetGate does not request your coordinates.
Save the current network and choose its profile. Networks with the same name are treated as one saved network. If macOS hides the name, connection types remain available. Choose whether an unassigned network keeps the last profile or turns traffic control off.
Keep the allowance in view.
Set a daily, weekly or monthly limit for the Mac or that saved Wi-Fi network. NetGate warns in the automation panel at 90% and requests a traffic pause at the limit. Checks are periodic, so some overshoot is possible.
A network limit counts traffic tagged after recognition is enabled; older untagged history is excluded. Recognized local traffic is excluded from network totals. These counters estimate usage and can differ from your carrier bill. To take control yourself, pause automation or turn traffic control off.