At comedian-school (if there is such a thing), they teach you that timing is everything.
The same is true in managing a project, and how proficient you are at getting the timing right will often be the key to glorious success or cringing failure.
Sometimes you will need to act immediately, usually to quickly defuse the potential onset of panic, a state often induced by people suffering from ‘little knowledge’ syndrome.
Other times you should bide your time and wait for things to pan out, often issues will resolve themselves or at least clarify themselves to the point that you can quickly determine a solution.
To some, the understanding of when and how to act will come naturally. Others will be able to hone this skill with experience. Managers who don’t fit into either of these groups will be those whose projects you will eventually be asked to rescue.