i use it every work out. one week ill use db and the next bb, after 3 hard sets of incline decline and flat ill do sone supplementary movements like cbles or flys
As of right now I don't do it at all; I do incline and flat. As well, I do flys. Next time I change up my lifts I will be doing decline. However, doing decline every chest workout is perfectly fine. Just make sure you change your lifts every few months.
The only time it's bad to feel the burn is when you're peeing...
i do it every workout. it's made a difference since i started it a month ago. not used to be sore but i change my chest routine up a little and now i'm gaining again.