Unlike commercial hardware standards, residential hardware is prone to various problems after prolonged use. Door locks, in particular, are high-load-bearing components, and even they are susceptible to malfunctions over time. It's common to see users and friends experiencing door lock damage due to improper use or maintenance.
Some points to note regarding door lock maintenance:
Lubricants: Some people like to apply lubricant to the keyhole when the lock feels stiff or tight. While this may make the lock smooth immediately, oil attracts dust, which can accumulate in the keyhole over time, forming a greasy residue that actually makes the lock more prone to malfunctions.
The correct solution: Shave some pencil shavings or candle wax shavings, blow them into the lock cylinder through a thin tube, then insert the key and turn it several times.
