Authors of a ten-year study of over 30,000 men found evidence that those who ejaculate more often may have a lower risk of contracting prostate cancer.
Men's Health reports:
[The study] found that men ages 20 to 29 who ejaculated 21 times or more each month were 19 percent less likely to be diagnosed with prostate cancer than those who ejaculated less often, between 4 and 7 times per month.
Men 40 to 49 who ejaculated at least 21 times per month reduced their risk of developing prostate cancer by 22 percent.
More research is needed to fully understand the link between ejaculation frequency and prostate health, perhaps for older men in particular, given their higher general risk. For now, feel free to keep on coming.
As for determining where to should finish, we've got another study to help with that.