Every circuit has a rated capacity, usually 15 or 20 amps. A space heater, a kettle and a microwave on the same line can pass that limit in seconds. If the breaker only trips when two or three appliances run together, you are looking at a load problem, not a faulty breaker.
A trip that happens instantly, sometimes with a crack or a burning smell, points to a short circuit or ground fault. Common causes are a damaged appliance cord, loose wiring or moisture in an outlet. Do not keep resetting it. Unplug everything on that circuit and book a technician.
Breakers weaken after years of heat cycling. One that feels warm, trips below its rated load or will not stay reset may need replacing. Because the panel stays live, this is a job for a licensed technician, never a DIY swap.
Switch off recently added equipment, then reset the breaker once. If it holds, spread your heavy appliances across different circuits. If it trips again, stop and call: repeated trips mean a fault is present.
Reset a tripped breaker once at most
Unplug high-draw appliances before you reset
Repeat trips mean a fault, so stop and call
Never tape or hold a breaker in the on position