Let continue with the third precept my teacher taught us :
"Be lazy, don't do things twice !"
This sentence can be a little ambiguous with the term "lazy" 
In fact, it means that :
- When a specific need is identified and well defined, it must be done.
- You have to design and implement it well as it is intended to be reused.
- Put in it all the necessary effort to do it right at the first time.
Indeed, being "Lazy" here mean that comparing the total effort made to do something right at the first time, will always be less that the sum of all the subsequents effort made to rework it afterward. 
So doing it well at first time is always better than providing a quick and dirty half finished solution. 