What is a potential disadvantage of using the APU frequently?

Using the Auxiliary Power Unit (APU) frequently can indeed lead to quicker depletion of fuel levels. The APU operates independently of the main engines and is designed to provide electrical power, air conditioning, and bleed air during ground operations. While it is essential for these functions, it consumes fuel whenever it is running. Therefore, frequent operation can lead to significant fuel consumption, resulting in a quicker drawdown of available fuel in the aircraft's tanks. Thus, maintaining an awareness of fuel levels is crucial, especially during extended operations or in situations where fuel supplies may be limited.

The frequent use of the APU does not inherently lead to quicker maintenance intervals. Maintenance is governed by several factors, including the unit's total operating hours and the specific maintenance schedule, making it less likely to be a direct consequence. While operational complexity might increase with the more frequent use of the APU, this aspect would not be considered a direct disadvantage. Similarly, the electrical system's performance is typically unaffected by APU operation; in fact, one of the purposes of the APU is to ensure that electrical systems continue to function efficiently when the main engines are not running.