Most of the time it will take about 12 to 20 minutes to rekey each lock. It also depends on the type of lock. These types of locks should take about 10 to 15 minutes each if the locksmith has a key to each lock he/she is rekeying (Schlage, Baldwin, Gatehouse, Dexter, Defiant, Promax, Master, Ace, Kwikset, Brinks, Pamex, Berlin, Modisch, Dynasty, Lawrence, Copper Creek, Emtek). For Best/Falcon Interchangeable Locks or ICC it will take about 20 to 30 minutes each to rekey the core because the locksmith has to setup the pinning chart and cut at lease 2 keys for the lock(s). One is for changing the core and the other is for the customer to open the lock.