Let me start with this: a picture taken on Legacy Pro 100 (aka Acros) and developed in XTOL 1+1:
Nothing special, except for the fact that the XTOL I used was from the bottle on the right:
left: fresh XTOL concentrated stock, right: 7.5 years old unopened concentrated stock.
I mix my XTOL in 2.5l water and in mid 2004 I decided to put away a full bottle of concentrate to periodically check its activity. Well, time went by and a few days ago I found the bottle. First I hesitated and thought that developer must be dead but a drop on a film leader told me it was not dead. I exposed a strip of film and developed as normal.
CI was down to 0.21 instead of the 0.65 I aim at. But a little contrast boost gave a quite usable picture.
Not bad for 7.5 year old developer.