Roger-

if you only print every couple weeks, then Ansco 130 is the stuff for you- even at working strength, it lasts for weeks at a time, and although it does eventually exhaust, of course, it never seems to. I remember putting something like 30 8x10s and nearly a dozen 16x20s through one gallon of the working strength (1:3) in a single session, coming back three weeks later and printing again and it seemed like it was still developing full tonal range on my prints in the same time (3 minutes). I had one batch going in my Nova slot processor for two months, replenishing as volume was consumed by prints and/or evaporation. Great stuff!