A CV and short motivation letter are often not sufficient to gain insight in the personality of the candidates. At the same time, there's a lot of information to further refine a first impression.

Motivational letters are not of utmost importance, but do add a nice personal touch to your CV. If you do decide to ... that you should keep the letter short as you do not want to bore the reader.

Can I just write a really short cover letter since all the information I would put in a letter is already on my CV? The cover letter feels redundant. NO. And the reason for that is — they are ...