There is no exact number of STARs you need to gather. STARs are used as documentation of a specific example of a time in which you performed above expectations or an area in which you need to improve your performance. Usually, more STARs received in an area shows consistency of performance in that area.
STARs are neutral.
No, you do not have to write the STAR on the STAR pad form. You may write STARs in e-mails, memos, or letters just as you would for a letter of commendation or a letter of complaint. Yes, STARs can be written by you about a specific example of your performance. This method is useful especially for employees who do not work alongside their supervisor. The supervisors who have used this method report it is a very successful way to ensure the task is completed properly.