When your life isn’t quite going how you anticipated. You might have the thought to start over. Often this takes a while to actually begin.
Starting over goes from being something scary that you choose to avoid (because you’d rather be unhappy with what you know than risk things being any worse if you try something new) to being something that is worth the risk.
The mindset goes from I’d rather stick with what I know and be miserable than venture out into the unknown to I’d rather venture out into the unknown than stick with what I know and be miserable.
As time passes, the value we place on familiarity in situations when we’re unhappy often decreases. It’s no longer considered worth it to stay in your current circumstances because if you’re unhappy now, the worst case scenario is starting over and still being unhappy. However, often things turn out significantly better.