Even if your store has a very deep tree, in 99.99% of cases the time required to update it is completely negligible compared to any re-render that React will ne

Even if your store has a very deep tree, in 99.99% of cases the time required to update it is completely negligible compared to any re-render that React will need to do afterwards (even when the DOM doesn't actually get changed). The 0.01% is if your action has to do some super-complicated computations to get the next state.