i did this with caffenol c spiked with ansco 130 for 6months.
it was caffenol made with sumatran beans ( 100% robusta )
and ansco 130 15cc / 750cc ... it was about 3L in total.
i processed maybe 200 sheets of film ( sheets of 4x5 + rolls of 120, 35mm, 110 )
c41_e6_b/w as well as sheets of paper ( 4x5 - 8x10+ hand rolled 122 spools with 6-7 exposures
of post card format paper )
eventually i got nervous, and dumped 2L and mixed fresh 2L ... but it was still going strong.