Thanks to all for the information and opinions.
Aggie--Technidol is used one-shot, so I was only concerned about prolonging the life of the original concentrate.
Ole--Thanks for the advice against refrigerating. A later post suggests that it probably isn't necessary anyway.
David/Mike--I didn't mention in the original message that I wasn't thinking primarily of Tech Pan; I ordinarily use Technidol Liquid for night shots on T-Max 100. Its a perfect combination: a film with favorable reciprocity characteristics and a soft-working developer. I have tried highly dilute solutions of HC-110 and Rodinal for similar exposures, but the results were definitely inferior to those obtained with Technidol.
glbeas/Annemarieke--Years ago, Technidol Liquid was sold here in small bottles, but over here each bottle made 16 oz. (473 ml). I still have a couple of the empty bottles. Currently, Technidol Liquid is sold in a box of six individual foil packets, each one for making 8 oz. of solution. Each box of six costs around $12.00. That certainly makes it a pain in the pocketbook for 120, but I manage 4 sheets of 4 x 5 (in a rotary drum) with only 8 oz.