The achievements you gain through education and training represent both acquired knowledge and your ability to develop. Many employers spend a lot of money on training and are looking to see if you are a person they should invest in.
Highlight any training undertaken through your own initiative.
Leave out any exams or courses in which you have been unsuccessful.
There is one simple guideline here. The more recent your education, the more complete the description needs to be. At age 23 your educational record will form an important part of your achievements, and will be of significant interest to an employer. However, at age 43 your employment history counts for far more and ...