Ask the question while the missing detail is still small.

Questions get harder to ask as time passes. On day one it is ordinary curiosity, by week three it suggests you were not paying attention, and by the time the whole thing depends on the answer, asking looks like an admission. Meanwhile the missing piece has been quietly shaping decisions, and the cost of not knowing has been rising the entire time.

Ask the small thing today, while it is still small enough to be a detail. Put it plainly rather than dressing it up. If you notice yourself saving a question until it feels safer, that is a sign the moment has already arrived.