I drain and fill my brake fluid every year. It takes under an hour and costs like $10. I also lube the caliper guide pins and check the rest of the brake components. I put new rotors and pads on all four corners around 75k or so (I forget the exact number) and am at 127k right now.
Replaced my pads around 60K. Check them each time I rotate tires. I tend to do them a bit on the early side though. Try to avoid doing any repairs in the winter. Cold weather makes things harder to do.