Not all work is equally urgent.
Classes of service set explicit policies for different kinds of urgency, so the team doesn't re-argue priority on every card.
Expedite
Drop Everything
Real emergencies, like a live outage. Limit: one at a time.
Fixed date
Hard Deadline
Costly if late: a regulatory change, a porting cut-over date.
Standard
Most Work
Taken roughly in order, within normal flow.
Intangible
Matters Later
No deadline yet, but ignore it and it bites: upgrades, tech debt.
If everything's urgent, nothing is.