You can also get most of the fluid out of the reserviors with a turkey baster, then just refill it. If you don't have a vacuum pump.

 

I bought a brake bleeder from Motive Products and it works great, better pedal feel than before. I used it on my Camaro that I put Corvette brakes on and fluid changes were done in a half hour by myself. Brake fluid does break down over time espescially when heated alot when driving down grades or lots of turns. Eventually it's boiling point gets lowered and your stops will take longer, pedal may go to the floor. This is definitely a fluid that must be changed but when it breaks down depends on how you drive. I couldn't say time wise how long it lasts but if you buy the bleeder it's pretty easy to do it yourself.