Every other paper developer I have ever used lasted longer than Dektol, with the possible exception of Bromophen which seemed about the same, best I remember (it's been years.) I've always hated Dektol for this very reason.
Originally Posted by Neal
There are two elements to tray life, or life of mixed working solution. One would be how many prints you can make before it's exhausted. I've never, ever, managed to hit that limit in a single printing session with any developer and once diluted Dektol is only good for a single session. That must be the one others are talking about. What's more important to me is, "can I pour it back into a bottle when I'm done, squeeze the air out and cap it, and come back next week to find a bottle of still good working strength developer?" LPD is the champ at this and what I mostly use, but I've been using Ilford WT some with WT paper and it lasts a lot better than Dektol too.