Prolonged periods of heavy benching really are only necessary if you are a powerlifter. And even among powerlifters the bench is responsible for more injuries than the squat or dead. The problem I see with the bench is that unless you are very well built for it (barrel chest, T-rex arms) then over time it will put a lot of strain on the shoulder girdle and the very small stabiliser muscles around that joint.
Having said that most people you see benching have atrocious form and are an injury waiting to happen (flared elbows, bouncing weight off chest). The best thing for long term shoulder health if you have to/want to bench is to leave your ego at the door and bring your grip in to shoulder width (about 18-20 inches apart). This grip is commonly called "close grip" but its actually not - a true close grip bench has the hands much closer together. The guys you see bouncing 265 off their chest with their arse up in the air would get stapled by 225 taking a shoulder width grip, bringing the bar to the chest, pausing briefly and pressing up.
But then again I have a shitty bench so I am biased against it. My push press is pretty much on par with my bench...
