Brake Fluid is the one u want to watch for water, absorbs water horribly, giving u spongey brakes...thats why u shouldnt use old brake fluid u got layin round the garage for brake jobs...always start w a new bottle...
I take a turkey baster and suck out all the old crap, get as much as u can out of it, wipe the resovior clean, (if its the type that allows this) and refill it....its better than nothing!
sorry, thought id just throw that out there...also, I agree with the guy above, change it both times, if u only put 3K a year on it...shit dude, drive it more!@!