Life will always happen, no matter your circumstances. While it would be nice to predict and accurately measure the next time there will be a disruption, the important lesson is to always be prepared.
Things fall off track during those times for a number of reasons.
Perhaps a relationship went astray, a good habit got disrupted, a bad habit returned, or a system fell apart. There are ample hiccups in life that are unintended.
The biggest one, of course, is the realization your life path is not the one you should be on anymore.
The important key to have in mind is taking steps to start again.
I look at it this way:
If the last ten years (or even twenty) went a certain way, I’m going to make sure the next ten go a different way.
There’s no point in dwelling on it anymore. Do your best to repair the harm (if any) and be prepared for the bumps that will come along next time.
Recognize what happened, learn from it and then start again.