What WD-40 actually does
WD stands for Water Displacement. It’s a thin solvent that pushes water away. Brilliant for ungluing rusted bolts. Terrible for lubricating moving parts long-term.
Why people misuse it
It DOES lubricate briefly, then dries out. Squeak comes back in a week, you spray again, and the cycle hides the problem. The right tool would have fixed it once.
The right tools
Bike chain → bike chain oil. Door hinge → silicone spray. Lock → powdered graphite. Squeaky drawer rail → white lithium grease. Each costs under $10 and lasts years.