A corner guard takes one morning if you do the steps in order. Most failures come from skipping the cleaning or the test, so the order matters more than the tool. This is for the corners she meets on the bed-to-bathroom trip: the bed frame at the foot and side, and any nightstand that sits on the route.
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Mark the corners on the route
Walk the trip in the dark, slowly, with the lights off. Notice where her hip or shin reaches the corner, not where your eye does. Mark each corner with painter's tape at that height. Mark only the corners on the route. A corner off the path does not need a guard, and an extra guard can block the path you want her to keep.
Check the guard against the corner
Hold the guard against the corner before you peel anything. Check that it covers the edge and the first few inches of each face. Check that it does not hit a drawer front, a bed rail, or a lamp cord. Check that it clears the walking path at its widest point and leaves room to pass the nightstand. If the corner is rounded or uneven, a flat guard will not sit tight, so choose a shape that matches the corner you actually have.
Clean and dry the surface
Wipe the corner with a dry cloth to take off dust. Then wipe it with a mild cleaner and let it dry all the way. Adhesive over dust or cleaner residue will let go, and the guard can come off on its own during the night. Do not skip this step and do not hurry it.
Set it, press it, and leave it
Peel the backing and set the guard with one edge first. Press from the center outward so no air stays under it. Then leave it alone for the full time the package gives for the adhesive to set. Do not let her lean on it, sit against it, or push a chair into it during that time. If the guard mounts with screws, drive them into the frame itself, not a thin panel, and check each screw before you move on.
Test it the way she will hit it
Push the guard from the side she will come from, with a steady hand, then pull at the edge. It should not shift, lift, or peel. Check that it has not created a new hazard: a loose corner, an edge that catches a sleeve, or a gap that traps a foot. Walk the route once with the lights off and the guard in place, slowly, the way she will walk it.
Keep the check and write it down
Name the person who checks the guards each week and the person who replaces them. Look for lifting edges, tears in the cover, and any soft spot. Replace any guard with a lifted edge or a tear, since those are the ones that catch a sleeve or a foot. Write the install day on the back of the guard, along with the name of the person who did the check.
If the route also has a loose rug, a tall nightstand, or a bed height that needs changing, those are separate jobs, and the Start here reading path lays out the order. Questions about her health, including whether a bump from a corner needs a closer look, go to her physician.