I wear a belt and use straps. The belt helps you keep good posture (among other things) which helps ensure you are working the appropriate muscles. The wrist straps give you a better grip so you can work certain muscles to their fullest without the weakness of your grip hindering that. Unless you are going to compete, and the competitions you compete in do not allow such items, why not use them? Using the appropriate accessories helps prevent injury, increase load/reps and they allow you to work the targeted muscle to its fullest; it just makes no sense for one to not use them.