Gather tools: new lock (same type and handing), screwdriver, drill/driver, measuring tape, pencil, chisel (if needed), masking tape, screws, and optional lubricant
Verify lock type and size: deadbolt vs knob/lever, single vs double cylinder, backset (typically 60/70 mm), and door thickness
Remove interior trim/handle/knob components per the lock’s instructions
If deadbolt: unscrew interior mounting screws and pull out the bolt assembly
If knob/lever: remove mounting screws, separate interior/exterior pieces, and pull out the latch/lock mechanism
Remove the strike plate screws and slide the strike plate out of the door frame
Remove the old latch/deadbolt bolt from the door edge
Clean the door edge and holes; remove old paint or debris
Transfer measurements: confirm backset and hole alignment (cylinder hole, latch hole, edge bore)
Test-fit the new lock parts without tightening screws
If holes don’t align: use the required template/plate for the new lock and adjust as directed by the manufacturer
Install the latch/deadbolt into the door edge, ensuring the correct orientation and alignment
Attach exterior and interior lock components, ensuring the tailpiece/spindle engages correctly
Tighten mounting screws firmly (do not overtighten)
Install the strike plate and align it with the bolt/latch
Close the door and check alignment: bolt should enter the strike cleanly without scraping
Mark strike plate position if needed, then adjust the strike plate mounting holes
Reinstall strike plate screws and verify smooth operation
Test key/turn action and latch throw; confirm door fully latches and retracts
Check for play or looseness; tighten any remaining screws
Reinstall any covers/trim pieces and ensure they sit flush
Lubricate the lock with graphite or lock lubricant if recommended by the manufacturer
Confirm correct operation for both sides (if applicable) and verify deadbolt engagement fully