Anybody with "Look" pedals and cleats, there arer tiny holes in the cleats which, when they are worn through, it's time to change the cleats. Also, you should check the screws often to make sure they are tight. Once a screw gets loose (especially a front one) you won't be able to clip in - no fun!! Your bike "tool" should have a screwdriver head which fits whatever screws you have.

Just my "2 cents".