I am still using the last of my bottle of green resin that came with my B9 Core printer. It was delivered to me almost 2 years ago in Feb or March of 2017?
No I don't print that much and my prints are just fine. I do figurously shake that bottle and let it sit so the bubbles subside for about a half hour before I add it to my Vat. I also leave my resin in the vat inside the Printer and pull it out and stir the resin so the white striation looking stuff is mixed well with the rest. I also use the white spatchula to wipe the window so the white stuff is removed from the window and is well mixed. Others remove the vats and tilt the vats so it settles in the well of the vat to mix it and the vat also benefits from the exposure to oxy that is needed to print on the PDMS type of window.
So the short answer is I have not heard of a shelf life unless it is contaminated or compromised by exposure to light.
I'm so far behind I think I'm First !!