I think once you smelled the overheating brakes, it's time to check them thoroughly. Nothing worse than the brake pedal going to the floor and no braking when you need it.
In my case, the sticking brake caliper had overheated enough to ruin the rubber seals inside and rebuilding was in order.
I don't know whether changing the brake fluid every year will prevent this kind of sticking calipers, but some say it does.
Have them checked asap.