My rule:
- One bulged in a monitor/PSU from same era: shotgun all same-value caps, they age together
- Random single failure in newer gear: replace that one + neighbors
- High-value board (medical, industrial): shotgun, do not risk callback
- Cheap consumer, customer pinching pesos: targeted, explain risk
Other techs: how do you decide? Customer usually picks targeted then complains when next cap goes.