How long before the exit you must be planning it?

The ideal timing for planning an exit strategy is at least 5-10 years beforehand. That kind of a diligent approach is proven to help you in accumulate as much of an assets as possible, whilst taking their price to the highest level possible, for a future sale. But unfortunately, that kind of diligent approach is not always applicable. So how does a CEO or an owner in a hurry can perform a quicker exit strategy, say in 1, 2 or 3 years?