What is a common cause for low brake fluid level in an Audi 80?

I recently noticed that the brake fluid level in my Audi 80 is below the minimum mark. I have checked for any visible leaks but have not found any. The brake system appears to be functioning normally. What could be causing the low brake fluid level?

The most common cause for low brake fluid level in an Audi 80 is normal wear and tear. As brake pads wear down, the brake fluid level will naturally decrease. Make sure to routinely check and replace your brake pads to prevent further decrease in brake fluid level.