It appears okay. One shouldn't need to ever top off brake fluid. It's a closed system so if there are no leaks then there's no brake fluid loss. It's normal for the fluid level to drop as the brake pads wear since there's a longer travel for the pads to contact which means more fluid in the system needed from the reservoir.
If the level in the reservoir drops fairly low and you don't think you have a leak then it's probably time to have the brakes inspected to see if the pads are worn to a point where the pads s/b replaced. Of course, if you think you have a leak it needs to be taken care of immediately.