If your lights are dimming more than normal it might indicate a bad connection somewhere on the circuit. If multiple circuits are affected and some lights are getting brighter than normal, you could have a bad connection on your outside service cables. Call your local utility company first to check power to your meter socket. (Eversource if you're on Cape Cod) A common problem is tree branches falling on overhead cables and pulling them out of the connectors. The next most common problem we find is corrosion on aluminum connections in the meter socket or panel. A load test is the most accurate way to find a bad connection to your electrical meter. If everything checks out with the utility company then call an electrician to check for loose connections or corrosion in the electrical panel.