I don't use one and have not for about 13 years. No, I have not trained the entire time but last time I had a partner was in 93ish, late 93. The guy I trained with was a monster, we trained like animals for about 6 months. I have never made bigger poundage increases in my life and left the gym everyday feeling like I got my ass kicked. He competed, I got sick and went to the hospital and was out of action for about 6 months. When I was finally cleared to train again he had stopped training all together, I tried to get him going again but he just wasn't into it. I never found anyone that could push me like that so I just gave up trying. Might be nice but it's not worth the hassle to me.