When you are deciding to jump from one career to another, or when you want to move to a different city. Or perhaps you want to decide whether to get married or to plan for another child. It would take a very long time to make such a decision before proceeding.
If the next question is when and you are stuck, you should only look at the negatives. For example it will be more risky moving to another city during a pandemic because it is difficult and very expensive to get flights. It might be a bad time to open a new restaurant for similar reasons. However, if you are waiting for some signals, then it is likely procrastination.
The mentality you actually get into should be one of no return. There may be a way to go back to what you used to have, but you should be prepared for an all in. Having a secondary backup plan often hampers progress or paints a different outcome. It may cause you to linger longer than you should. The comfortable past will call back to you at different difficult times. Sometimes that is warranted and you really do need to go back. But stick with it 100% and see it through as far as possible.
This mitigates timing risk. When we wait for a certain opportune time, what we are also doing is giving ourselves an easy way in and more excuses to fail. Good times don’t last forever, so you need to be able to move forward even if it has gone past that point. There is no point to go in at a bad time though, that is just asking for trouble.