Are you talking about long tray life or long life of the stock solution? Most stock solutions keep pretty well. I use Defender 54-D, and it keeps for up to 6 months in a partially filled bottle. Ansco 130 has a good reputation, but it seems to fade after about three months. I suspect D-73 (Dektol) is about as good. Formulary BW-65, which is an Ansco 130 variant, divides the developing agent from the alkali to achieve long life (about four to five months, in my experience).