Mental shortcuts, or rules of thumb, make quick, efficient judgments and decisions, especially when facing complex problems or incomplete information, by replacing a difficult question with an easier one.
However, I actually don’t do that most of the time...
Because I think it’s better to wait and use true logic to solve a problem; otherwise, a decision that I regret will be more likely...
Though, looking back, contradicting my previous self, honestly, I might still be using them quite a lot, because most things in life don’t actually need deep thinking. Perhaps as a child I was called out for being impulsive and thus wanted to avoid being called out by faking myself as being a very deep thinker! This disregards the fact that heuristics still have lots of pragmatic use! To give the easiest example, you’re so used to walking, when it involves complicated leg movements (multiple muscles) and body-balancing.
It’s an efficient tool; without it, time would elapse and human energy would be drained too much. According to the dual process theory, such actions become so habitual that you don't need to think about them (breathing, walking, talking, etc.)