There really is a benefit to 'sleeping on it'.
The optimal approach is to ensure you are well informed and to use techniques to overcome the biases of thought and emotion that are known to skew human rationality. So, begin by gathering background information on the decision, making sure you draw on diverse, reputable sources.
Now, one bias that could lead you astray is the ‘affective forecasting error’. Essentially, we’re poor at anticipating how we’ll feel in future situations. To get around this, find out how other people similar to you felt after making a given choice.
Another relevant bias relates to ‘temporal discounting’ – we tend to prioritise short-term gains over long-term consequences. For instance, you might agree hastily to a future commitment (such as taking on a new project at work or going on holiday with a friend) because the immediate benefits are salient, in terms of kudos or popularity, but you underestimate the investment of time and effort required in the future.
When faced with these kinds of scenarios, try to imagine how you would feel if the commitment were imminent – if you had to work on the project this week, or get ready for the holiday next weekend.
Once you’ve completed the above steps, it is a good idea to compile a list of pros and cons of your options and to use a systematic scoring system to ground your decision. That said, you don’t want to completely neglect your gut instincts or tacit knowledge. So, do your scoring and then sleep on the decision and see how you feel in the morning. That way you’ll have drawn on a healthy mix of mind and heart before you make the leap.