Once is a mistake.  Twice is a choice. 

There are too many mistakes in this world to make once.  

Don’t exponentially increase the number of mistakes there are available to make by repeating one.  

Mistakes can be very useful.  

When you make a mistake and learn from it,  that mistake is not as a waste.  

When you make a mistake, and you do not learn from it, well, that is a waste of time and energy which are both in limited supply in life. 

Don’t waste either by not applying a lesson that you have already paid the price to learn.