No experience with the Fuji kits, they seem to be unavailable in the US.
I have used the Kodak 5L kits and streeeetched them.
Several months back I ran some chromes from a kit that was on the second or third 1 litre batch so call the kit half full. The kit had to be 8-10 months old and not resealed under nitrogen or anything else.
I had already went over capacity for that particular 1L batch and the chromes looked fine to the eye but I didn't do any definitive tests for color accuracy or density other than inspection on a light table.
I cant remember when I mixed that 1L batch but it had to be 3-4 months in a full 1L bottles.
I mix 1L working solutions for a 2 roll tank.
These are stored in full 1L PET bottles but the kit it is pulled from is just stored in the original bottles.
I'm about to run some more within a week or so.
I'll mix "fresh" from this kit and report back if I can remember to find this thread.