Charles;
Don't pour it out. Check it out. If it is still good, use it. It goes until the last gasp and then begins to turn dark yellow then orange. That is when to throw it out. Don't waste it!
PE
OK as an experiment, I made 42 5X7 prints on Sunday with a litre of the mixed Liquidol. (100Ml of concentrate) At the end of the day, I stuck the remainder in a Amber Glass 1 L bottle.
(I have been printing some 30 year old negatives taken when I did not know how to develop film so I could post them at:
http://www.facebook.com/album.php?aid=2030677&id=1573530156&l=86e6ac5195 )
Today I put it back in the tray and found it was a sort of Grey/Purple colour. Pressing on I made another 20 5X7 prints, and found the the colour of the developer was getting Darker, but still basically grey. The prints had good dark areas so I put it away again.
I did find that the darkening made it hard to see the pint comming up, but the image was still appering at 30 seconds. I let everything "Cook" for 90 seconds in the interest of consistancy.


and i use it for a print developer now too !