The day is interrupted by definition. A lockout at eleven cannot wait, but neither can the lock change booked for a tenancy starting at noon, and unless both sit in the same schedule the outcome is decided by chance.
The van is the warehouse. Which cylinders, which standards and which sizes are on board determines whether a job finishes now or needs a second visit at the locksmith's own expense.
Master key records need real care. Which keys open which doors, who holds them and when a system was last changed is genuinely sensitive information, and it has to be both retrievable and protected.
Letting work recurs on its own calendar. Lock changes between tenancies happen on dates somebody already knows, and a locksmith who asks an agent for next month's list rarely has an empty morning.