We usually don't think about how much we rely on our home's electrical system until a power outage forces us to do without. Electricity is responsible for powering the home's appliances, lighting up rooms at night, and keeping the temperature at a comfortable level.

Unfortunately, it can also be difficult to determine whether the electrical system is in good condition. Most of the wiring is hidden within the walls, making it difficult to access. You'll need to keep an eye out for telltale signs of trouble when determining if an electrical update is necessary.

The age of your home can be one hint as to the quality of your electrical system. Homes dating back to before 1940 may still have knob-and-tube wiring, named for the insulating knobs and the tubes used to carry the wires. Kolb Electric, a company based in Lorton, Va., says homes built or updated between 1965 and 1973 frequently used aluminum wiring, which was valued as a cheaper alternative to copper wires.

Both options can present significant safety issues. Aluminum can react with materials in outlets, light fixtures, and other parts of an electrical system; this can cause the material to overheat and spark a fire. Timothy Thiele, writing for the home design site The Spruce, says knob-and-tube wiring isn't inherently dangerous, it can't be modified with a grounding wire. This means that the system can't service three-pronged outlets, although it can be set up with a ground-fault circuit interrupter to cut power in the event of a power surge.

Older electrical systems generally carry fewer safeguards than newer ones, leading to a higher risk of fire and other hazards. Jamie Dent, writing for the home design site Angie's List, says overloaded circuit breakers may not trip in older systems due to loose connections or other problems. A previous homeowner may have also made the unsafe modification of replacing the breaker with a larger capacity one to prevent frequent trips, even though the wire is not rated to carry the higher electrical load.

Even though modern appliances are often rated to be more efficient, a household's electrical use may be too much for the home's system to handle. Kolb Electric says the demand created by computers, appliances, smart home features, and other items may be considerably greater than what the system was built for.

If you're constantly experiencing a blown fuse or tripped breaker, it's a warning sign that your electrical use is exceeding the system's abilities. You may also notice that the lights dim or flicker when you run an appliance, since the electrical system isn't able to reliably service both.

In serious cases of electrical overload, you may notice a buzzing, crackling, or popping sound coming from an outlet or switch. Donna Boyle Schwartz, writing for the home improvement professional Bob Vila, says you may also notice smoke coming from an outlet or appliance. The safest thing to do if you notice this kind of problem is to shut off power at the main breaker and call an electrician to diagnose the problem.

Outlets and switches should be cool to the touch. If they are warm or have visible scorch marks, it's an indication that the wiring situation is unsafe. You'll also want to make sure all electrical connections to an outlet or switch are secure, replacing any plates that are missing or damaged.

Be aware of any issues with your electrical system if you have noticed signs of mice in your home. Rodents can chew on your wiring, creating frayed wires and other problems.

When you can inspect the wires directly, make sure they are in good condition. Thiele says the insulation should not be cracked, missing, or damaged. Any places where wires have been spliced together but remain exposed should be properly covered.

An update to your electrical system may require you to go beyond the wiring itself. Dent says this work can include upgrading the panel, meter, and circuit breakers so that the system can safely receive and distribute more power. This update also gives you the benefit of being able to add new outlets and replace outdated ones.