Score competing work on reach, impact, confidence and effort so the argument is about evidence.
Use when Use it when you have many comparable candidates competing for one team's capacity, when prioritisation has become political and you need a neutral vocabulary, or when you need to explain to stakeholders why their request did not make the cut without it being personal.
Avoid when Avoid it for work that is not discretionary — security fixes, legal obligations and keeping the service up do not get scored, they get done. It handles strategic bets badly: anything genuinely new scores low on confidence and reach by construction, so a team that follows RICE mechanically will optimise itself into small safe increments forever. It also cannot see dependencies or sequencing.
Separate urgent from important, and notice how much of your week serves neither.
Use when Use it when you are busy but not progressing, when a team is permanently reactive, or during a periodic review of where a role's time actually goes. It works well as a recurring habit rather than a one-off, and it is a useful device for a manager and report to look at a workload together without it becoming personal.
Avoid when Avoid it where you have little real autonomy — telling someone to delegate work they cannot delegate is just a way of blaming them for their constraints. It handles individual tasks better than long collaborative efforts, and it has nothing to say about work that is important to someone else and not to you, which is most of what makes a job hard. It also assumes you can tell importance from urgency, which is exactly the skill people struggling with this tend to lack.