Well I make a gallon of STOCK solution from the yellow Kodak envelope.
Then you dilute that Stock solution to a WORKING solution (immediately before printing session) depending on what look you are after.
There is more info regarding dilution here on apug and can inform you better than I.
If I run a short session and don't use say that 1-2 litre of WORKING solution I just diluted I will sometimes save it for tomorrow for contact sheets if blacks aren't super critical.
Once the STOCK solution is diluted to WORKING solution it doesn't keep as well so you will ultimately be the judge on how far you want to stretch it.