Since rebuilding my darkroom I've been using LPD at 1:1. In the old days I always used Dektol. I have a plastic 1 gal. milk jug with about a quart of used 1:1 LPD in it. I used it yet again yesterday and, even though it is piss yellow and throws a greenish gray sediment in the tray, it still appears to work fine. The first signs of an image still come up in about twenty seconds, the blacks are still deep black even before toning and the grays are all there. It doesn't even stink. I'm really loving it.
At what point does this stuff die? How can I first tell? Is using it at this age and with this appearance injurious to the longevity of the prints?