Pang Nam Fui 
Three visible traits name a selection, and I read them in order: the white marking pattern, then the blade surface, then two measurements taken with a plain rule. No flower is needed and no root ball comes out of the pot, which is why an unlabeled shelf plant is rarely a mystery.
Cut tissue never grows back, so I finish all three looks before a blade touches the leaf. Where the mark sits, whether it has stopped spreading, and how it feels under a thumb name the cause between dry air, salt in the water and a sun-struck patch on my peace lily.
The surface lies, so I stopped watering to a calendar and started reading the pot instead. A lift the day I water and another three days later builds a scale nothing else can give me, and the pour ends when the saucer fills rather than at a measured volume.
A peace lily stores no water of its own, so everything the roots draw on has to come from the medium around them. No bag prints the number that actually decides it, which is how much air that blend still holds, and I have learned to settle it by hand.
The pain here is a physical wound rather than a poison the body takes up, which changes every part of the response. I handled a division bare-handed once and my fingertips stung for an hour, and that is the same mechanism a pet meets when it bites a peace lily leaf.
Caring for a Monstera deliciosa comes down to four things I get right every week: light bright enough to cast a soft shadow, a chunky mix that drains fast, water judged by depth, and a pole to climb. The rest of this page is detail.
Every yellow leaf I have chased on a Monstera deliciosa turned out to be a root-zone story rather than a feeding one. I push a skewer two or three inches down, read what it brings up, change a single thing, and let the next leaf tell me whether it worked.
The first Monstera deliciosa I lost to root rot looked healthy above the mix right up to the day it collapsed. Since then I bare the root mass, work along every strand with my fingertips, and let what has gone soft decide where the blade goes and how small the next container must be.
I stopped watering my Monstera deliciosa on a schedule after two plants crisped at the margins while the mix sat bone dry. Now I check the top inch or two with a finger, water until it runs from the drainage hole, and tip the saucer out. That one habit ended the guesswork.
I sprayed blind for a season before I learned to name the pest on my Monstera deliciosa first. Silvery scrapes, fine stippling, cottony clusters and dark specks each point somewhere different, and the hand-removal pass does more than any bottle I have tried.