I have been using a 1 gal kit for 3 years now with no visible degradation.True, no contrast control, but other features make it my all round developer of choice. I regularly shoot TriX 400 @ 800 with superb results. It does well on Neopan 1600 at box speed. Ilford Pan F at 50 to 80 produces excellent negatives with superb gradation. I use Diafine for almost all my work. I like it .