2000 SE losing brake fluid

You have a to have a leak. Plain and simple. Since you are adding fluid only once a month, the leak is likely small. It could be from any of the connections, hoses, or even one of the bleeder screws. Take a bright light and look at each connection carefully - you might find stains/dirt stuck near the leak.

The only time you should need to add fluid to the brake system is when the pads start to wear and get thin. In this scenario, the calipers need extra fluid to extend the piston further to compenstate for the wearing pads. Even in this case, you should make sure the pads don't need replacing before topping of the fluid.

Cheers, Nirav