Your breaker panel is supposed to be boring. You flip a breaker once in a while, and otherwise forget it exists. When it starts drawing attention, it's usually trying to tell you something.
Breakers that trip often are the most common warning. Occasional trips from a space heater and a hair dryer on the same circuit are normal. Breakers that trip with ordinary use, or won't stay reset at all, point to an overloaded circuit, a fault in the wiring, or a breaker that's wearing out.
Heat, smell, and sound come next. A panel cover that's warm to the touch, a faint burning or plastic smell, or a buzzing or crackling sound all mean something is overheating. Switch off the main if you can do so safely and call an electrician right away.
Look for rust, water stains, or scorch marks inside the cover. Moisture and electricity don't mix, and scorch marks mean an arc has already happened.
Finally, consider age and capacity. A fuse box, a panel with no open slots, or a panel brand with a known failure history is worth having inspected, especially before you add central air, an EV charger, or a heat pump. A replacement is usually a one-day job that removes years of worry.