Cucumbers don’t last more than a few days in the fridge once cut. So as not to waste mine I make cucumber water.
You can keep a pitcher of it in your fridge, but I just add a few slices as needed until the cucumbers gone, accelerating it near the end as the cucumber starts to turn.
Extra oranges, lemons, limes also work for this. With citrus, I try to zest some of the peel into the water and let it sit for a while.