I always do a break check as part of the prelanding check. On 2 occasions I have found no brakes when they worked fine on the way out.. The first was in a Seneca. There was a pinhole leak in the brake fluid reservoir and all the fluid leaked out in the course of a 3 hr flight. The second was in a Nanchang (pneumatic brakes) and was the result of no air pressure due to a failed air line.