For years and years I used Agfa multigrade paper developer. It came as stock in one gallon bottles. I liked it just fine. I bought 3 gallons when a local lab closed down. It's all used up now and I've been using dektol. I mix up the 3.8 liters, then decant into 750ml bottles to prevent oxidation. Just opened up a full stoppered bottle - all brown, exposed test strip developed in the light still not black after one minute. No printing today after all. Between the home renovations we've been doing the last couple of months, and my struggles with carbon printing, the chemicals for silver printing haven't been used as often as usual, but I thought a full stoppered bottle should last at least 6 months. I really liked the Agfa. It kept and kept and kept, kinda like Rodinal. Any suggestions? Does the Ilford MG developer keep well? Even half full and gathering dust for months?