Co'r Ron, I will also have to engage brain.
I will let this sit in my mind overnight.......... Bit of a cheat answer as the expert is on the case.
Two quick thoughts come to mind re developer.
My rule with mixed developers was to store in glass airtight bottles. I will look tomorrow but there was an inert gas that could be used to expell air before screwing on the cap. In this form it will last well. If air gets to it, it will degrade quite quickly. Same applies to dish deleloper for prints.
2nd rule always use fresh developer. Do not put dev that has been used or exposed to atmosphere for any length of time in with fresh.
You will certainly enjoy Monday.
Will check back tomorrow.
Don