How long should the frozen horizon be for imported goods?

The conventional rule is that the frozen period should cover at least the review time plus the lead time to obtain the goods, because that is the window in which a change genuinely cannot be absorbed. For an importer with a six-month lead time, that arithmetic gives a frozen horizon of roughly six months, far longer than the one to four weeks typical in manufacturing.

The more useful framing is to stop treating it as a single number. What is truly frozen is what has already been committed: orders in production, on water, or in customs. What lies beyond the next order placement date is not frozen at all, even if it falls inside the lead time window, and it should keep being re-planned as demand signals arrive.

Teams that set one long fence and let the whole horizon go rigid lose the ability to react at the only point where reacting is still free, which is before the next order goes out.