Brake fluid check is a check you don't have to da that often.  Make it from time to time, but do it. The only time there won't be enough fluid is when you have a brake system leakage or serious overheating of the brakes. (Like in long hill descents, when you use the brake frequently)

Brake fluid check procedure

1. Our advice (as with all other fluids that go in the car), have a spare bottle of everything. If not, in this case, buy a break fluid that has the same specifications as the one in your car.
2. Look at the side of the break-fluid container, you'll see min-max gage that shows you the level of fluid inside.
3. Pour the fluid slowly inside and don't overfill.

Brake fluid bottle
4. Close the cap of the container tightly

Almost all cars have a signal emergency light if the break fluid is on minimum. However don't let it get to that point, because the brake fluid will probably be at the very minimum. If there is a frequent fluid loss, check your brakes immediatly!!