Final answer:
Air tanks should be drained a) monthly to prevent moisture accumulation and maintain optimal performance.
Step-by-step explanation:
When it comes to air tanks, it is important to regularly drain them to prevent any moisture from accumulating inside.
This moisture can lead to corrosion and reduce the effectiveness of the tank.
The frequency at which air tanks should be drained depends on various factors like usage, environment, and tank size.
As a general guideline, it is recommended to drain air tanks monthly to ensure optimal performance and longevity.