Here are the top three indicators that your electrical panel should be changed.
Your electrical panel has been in service for more than 25 years.
While you should avoid replacing a functional panel, if it is more than 25 years old, you should get it evaluated by a competent electrician. Even if your home's electrical panel appears to be in good condition, modern houses have more electrical needs than in the past, so even if your panel does not need to be changed out, it may need to be brought up to date.
Your panel is hot or has a burnt odor.
Overheating should cause your breaker to trip, safeguarding your house from fire.  However, if your electrical panel is hot to the touch or smells burnt, this might show a considerable hazard.
You've seen rust on your electrical panel.
Rust is a terrible indicator for your electrical panel since it indicates water damage. If you fear water damage to your panel or notice rust or corrosion on it, you should contact an electrician immediately to have it evaluated.