Sounds like you were negligent about flushing your brake fluid, thus your brakes are corroding from the inside. Any time you see "brown" brake fluid in the reservoir, that's rust in your system.

You should flush them every 3 years. Buy yourself a Motive kit and do it yourself. You can probably do this job in 30-45 minutes without any assistance, and doing it yourself will more than pay for the Motive bottle the first time you use it. Having a floor jack speeds the process.