A circuit breaker trips as a safety measure, cutting power before wiring or an appliance can overheat. An occasional trip usually has an obvious cause, but a breaker that keeps tripping is telling you something needs attention.
The most common cause is simply too many appliances drawing power from one circuit at once, particularly with heaters, kettles, microwaves or hair dryers. Spreading high-draw appliances across different circuits often solves this immediately.
If a breaker trips as soon as one particular appliance is switched on, that appliance (or its cord) is the likely culprit. Unplug it and get it tested before using it again.
If the breaker trips with nothing unusual plugged in, or trips immediately every time it's reset, there may be a fault in the circuit's wiring itself. This isn't something to keep resetting and ignoring, it needs a licensed electrician to trace and fix.
Older switchboards weren't built for modern loads like ducted air conditioning, EV charging or multiple entertainment systems. If tripping started after adding a new appliance, the switchboard itself may need upgrading.