Homegrown Video measures its retention in decades. We literally have fans that have been watching us and collecting our stuff since 1983. Our plugin is incredibly affordable and includes all our video and gallery content and is divided conveniently into a variety of niches.
We have won fan choice awards at AEBN, more AVN awards than any other amateur video company on the planet. The most popular show on the Playboy channel for over 6 years was "Naughtiest Home Videos" and that was primarily our content. Newsweek declared "Homegrown Video is the longest running series in the history of porn".
I could go on but that should give you an idea. Everyone can say their content helps retention. I can give you the certainty of it.