Quote Originally Posted by EdSawyer View Post

Once mixed, I try to use up the C-41 batch in a week or two if possible. The longest I think I kept a mixed batch of C41 developer without it going bad was about 6 or 8 weeks, but that was a stretch and it was pretty oxidized and not working great by the end.
As has been posted before by myself and others, developers will last a lot longer if stored properly. If stored in glass jars ( I use canning jars) filled to the top and tightly sealed, developers can last years and only slightly change color. I have both C-41 and RA-4 developers I mixed in 2008 that are still giving excellent results. Rather than mix from concentrates as I need developer, I mix a whole batch and store it away.