DeepThroat_#2: I just LOVE (he said sarcastically) all the statistics on this one! What, exactly, are you guys basing these numbers on? My guess is that you're assuming that ALL men are just like you. Well, guess what...they're not.
Well, as a psychologist who has studied these kinds of behaviors for over 12 years, I can tell you that at least a hundred factors are involved in this issue. Age is probably the strongest. The REAL research shows that, just after boys hit puberty, they jack off just about every day (often more than once per day). After their teen years have passed, things usually start to slow down.
Of course, some men have higher libido than others, so the numbers vary a lot. We still have very good data, however, that show that most men are still actively pursuing sex just about every day into their twenties, but only a small percentage actually masturbate every day during this time. Most research has hovered around two to three times per week. If man past his teens is masturbating two or three times per day (as someone on here said), it may be cause for concern. Such behavior is considered obsessive, and could be a sign of a deeper problem.
As we mature, sex and sexual relationships are still very important driving forces in our lives, but the next major change in masturbatory behavior doesn't happen until our 50s. By this time, the libido of most men has slowed considerably. Testosterone is not produced in the large quantities it once was, and the pursuit of all things sexual takes a back seat to other activities.
As men progress toward 60s, more than half experience some form of impotence. This has changed dramatically with the introduction of drugs like Viagra, however, so most impotence can now be treated well into older adulthood.
Some of the most interesting research I've read on masturbation frequency involved the attractiveness of the man (and NO, it's not all in the eye of the beholder, it's based upon symmetry and several other mathematical measurements...even babies at 3 months will look longer at pictures of attractive faces, and by 6 months, they turn away from unattractive faces). It seems that men who are considered extremely attractive have sex earlier in life and more often than those of us who are more normal looking, AND they masturbate less frequently. This may have something to do with the fact that they have greater access to sexual partners, and therefore, have less need to satisfy themselves, but some theorize that their attractiveness leads to a sort of "unconscious confidence" that makes them less obsessed with sexuality. In other words, they unconsciously feel that, since they can have sex whenever they want to, there's no need to think about it all the time. It reminds me of how kids only want candy when we tell them that they CAN'T have it. : )
Sorry such a long answer, but it gets frustrating reading all these opinions that are expressed as fact...especially when the questions are sometimes very important and emotionally charged.