Arrived on site to perform heating tune up on a 2006 carrier unit. Client stated no issues. Cycled heater. He will buy and replace filters himself. Advised him to be doing so every 3 months. Unit is operational. Checked electrical compartment. Blower wheel is is dirty from dirt entering unit. Motor is good. Slight dried oil. But in range of amps. Inducer motor is in range of amps. Unit is heating home up good. All safety switches are good. Drain lines both primary and second got to the same line. No safety over flow switches. Recommended adding one to prevent water overflow in attic. Igniter okay. Flame sensor is really oxidized from use. Cleaned but still worn out. It’s still operational just not the best condition. Temperature rise is in range and heating. No protection is on unit and recommended adding to protect unit from electrical surges and power outages that can damage or even short out unit and it’s components. Cycled unit and went over how unit is running. Went over rec