Andy, I'm mixing up 2L of working solution 1:1 and have been using it for 3 months now, no signs of exhaustion, though it is nearing the end, I keep track of prints run through it. If you're a fan of Ilford Coldtone developer, maybe you want to try omitting the bromide and substituting benzotriazole. This is what I plan to do with the next batch of PF130 I mix up. I'm happy with it now, but if I could get cooler tones from it that'd be better. I'm printing on Ilford MGWT and Oriental fiber papers.