The cut happens on a Sunday because that's when you have the nerve. You have sterilized the blade, laid out sphagnum that's been soaking since morning, set the perlite aside, found the chopstick you use to tamp. The Philodendron on the shelf — a verrucosum from an Ecuadorian line, four leaves, the new one still half-furled and bronze — has thrown an aerial root the length of a finger. You have been watching it for weeks. Today is the day.
And then you stand there with the knife and realize you don't actually know which node to take. The top one, with the freshest growth? The middle, with the fat root? The basal node down by the substrate, hidden under leaf litter, smaller and more reluctant? They are not the same cutting. They will not behave the same in the box. One of them will root in three weeks. One of them will rot.