Studies have shown that the actual use of Thrust reversers have a very minimal if any effect at all when it comes to stopping an airplane, hence when they compute stopping distance they dont account for thrust reverseres being deployed. We "pop the buckets" to help create drag and bring the nose down but thrust reverser's are probably used by many because of the super cool sound they make

not to mention how much sh*t they can throw into an engine as well as waste gas..............
PS the guy above says his landing would be "very interesting" if he didnt deploy the Thrust Reversers??????????????? Come on bro, If you are relying on that to get the airplane stopped you landed way too long and should have went around in the first place..........
Phoenix don't listen to anyone go out there and get the ******* job, dont let anybody, especially those who think Thrust Reversers saved there ass from going of the end of the runway, tell you any different